Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 18-01-08 14:37, David Newall wrote: The problem is that _p is widely used for non-ISA devices. Yes, we know, it's being fixed. Piss off. Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene, Here is why you shouldn't leap so quickly to rudeness. Everything is being repeated over and over and over again (as you put it) because people like you shout down people like me without making any apparent effort to understand the truth of the problem. Rene Herman wrote: > We've already talked about ISA bus speed, and how it's not in a sane > sense portably determinable, we've already talked about kernel > parameters, about udelay and it's usefulness in early boot, about how > your rude "Junk I/O" is exactly what is needed for some ISA devices > and so on... The problem is that _p is widely used for non-ISA devices. For example, a quick grep reveals the following (and more) all use outb_p: ./i2c/busses/i2c-amd756.c ./i2c/busses/i2c-ali1535.c ./i2c/busses/i2c-ali15x3.c ./i2c/busses/i2c-i801.c ./i2c/busses/i2c-piix4.c ./i2c/busses/i2c-viapro.c ./i2c/busses/i2c-nforce2.c ./i2c/busses/i2c-ali1563.c ./telephony/ixj.c ./char/pc8736x_gpio.c ./char/epca.c ./char/dtlk.c ./char/watchdog/w83697hf_wdt.c ./char/watchdog/wafer5823wdt.c ./char/watchdog/wdt.c ./char/watchdog/sc1200wdt.c ./char/watchdog/pc87413_wdt.c ./char/watchdog/wdt_pci.c ./char/watchdog/w83977f_wdt.c ./char/watchdog/pcwd_pci.c ./char/watchdog/w83877f_wdt.c ./char/watchdog/mixcomwd.c ./char/watchdog/w83627hf_wdt.c ./char/watchdog/advantechwdt.c ./char/watchdog/ib700wdt.c ./char/watchdog/pcwd.c ./char/watchdog/wdt977.c ./char/rocket_int.h ./char/sonypi.c Most of these go nowhere near the ISA bus. This has been said before, but perhaps you missed that. Which is another reason to use good manners, isn't it? The argument that you can't know how long to delay is utter rubbish. > In fact, we're blue in the face from talking about it. So say > something useful or go away. I think I'm saying something useful. I'll keep an eye out for your humble apology. (Are you big enough to give one?) In the mean time, perhaps you'll follow your own advice and say something useful or go away. :-p I hope you'll see this in the positive and constructive light that it is intended. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene, Here is why you shouldn't leap so quickly to rudeness. Everything is being repeated over and over and over again (as you put it) because people like you shout down people like me without making any apparent effort to understand the truth of the problem. Rene Herman wrote: We've already talked about ISA bus speed, and how it's not in a sane sense portably determinable, we've already talked about kernel parameters, about udelay and it's usefulness in early boot, about how your rude Junk I/O is exactly what is needed for some ISA devices and so on... The problem is that _p is widely used for non-ISA devices. For example, a quick grep reveals the following (and more) all use outb_p: ./i2c/busses/i2c-amd756.c ./i2c/busses/i2c-ali1535.c ./i2c/busses/i2c-ali15x3.c ./i2c/busses/i2c-i801.c ./i2c/busses/i2c-piix4.c ./i2c/busses/i2c-viapro.c ./i2c/busses/i2c-nforce2.c ./i2c/busses/i2c-ali1563.c ./telephony/ixj.c ./char/pc8736x_gpio.c ./char/epca.c ./char/dtlk.c ./char/watchdog/w83697hf_wdt.c ./char/watchdog/wafer5823wdt.c ./char/watchdog/wdt.c ./char/watchdog/sc1200wdt.c ./char/watchdog/pc87413_wdt.c ./char/watchdog/wdt_pci.c ./char/watchdog/w83977f_wdt.c ./char/watchdog/pcwd_pci.c ./char/watchdog/w83877f_wdt.c ./char/watchdog/mixcomwd.c ./char/watchdog/w83627hf_wdt.c ./char/watchdog/advantechwdt.c ./char/watchdog/ib700wdt.c ./char/watchdog/pcwd.c ./char/watchdog/wdt977.c ./char/rocket_int.h ./char/sonypi.c Most of these go nowhere near the ISA bus. This has been said before, but perhaps you missed that. Which is another reason to use good manners, isn't it? The argument that you can't know how long to delay is utter rubbish. In fact, we're blue in the face from talking about it. So say something useful or go away. I think I'm saying something useful. I'll keep an eye out for your humble apology. (Are you big enough to give one?) In the mean time, perhaps you'll follow your own advice and say something useful or go away. :-p I hope you'll see this in the positive and constructive light that it is intended. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 18-01-08 14:37, David Newall wrote: The problem is that _p is widely used for non-ISA devices. Yes, we know, it's being fixed. Piss off. Rene. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 17-01-08 22:58, David Newall wrote: Rene Herman wrote: Over the course of a 100 messages or so in this thread it's been determined that the best course of action is to keep the out for ISA and replace it with udelay() for chipset logic. Now go away. Rather than this incredible rudeness, why don't you direct your energy towards convincing Alan of this. He's the hold-out. No he isn't and that's why I'm rude -- everything needs to be repeated over and over and over again. Read the thread(s). You didn't limit your reply to chipset logic and Alan even already submitted patches to isolate the delay for the chipset logic (PIC and PIT that is) where the expectation is that a simple udelay() will suffice. We've already talked about ISA bus speed, and how it's not in a sane sense portably determinable, we've already talked about kernel parameters, about udelay and it's usefulness in early boot, about how your rude "Junk I/O" is exactly what is needed for some ISA devices and so on... In fact, we're blue in the face from talking about it. So say something useful or go away. Rene -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene Herman wrote: > Over the course of a 100 messages or so in this thread it's been > determined that the best course of action is to keep the out for ISA > and replace it with udelay() for chipset logic. Now go away. Rather than this incredible rudeness, why don't you direct your energy towards convincing Alan of this. He's the hold-out. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> In the early days of clone PCs, as you know but perhaps many on this > list might not, the bus speed could be changed, but this was > user-selectable. For such a machine, delay values can be pre-calculated > for each bus speed, and a kernel parameter set accordingly. Or are you > saying that the characteristics of the bus on a given machine vary for > reasons other than user selection? They vary based on the CPU clock, the dividers from PCI to ISA on PCI based boxes, and on the ISA only ones often on the CPU speed. Unfortunately the way you control that divider or read it is chipset specific. Nor would it be reasonable to expect the end user to set it. For PC/104 systems the same applies today. > The question is, for a given machine, can we determine a delay value > instead of using a junk I/O? The question (for ISA peripherals) is "why bother", and with the 8390 patch there are one or two dubious PCI driver users of _p left but not much else that isn't ISA or chipset logic. The question for chipset logic where it has become integrated is "can we get rid of it for some devices, if not what can we use instead" Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 17-01-08 14:36, David Newall wrote: In the early days of clone PCs, as you know but perhaps many on this list might not I'm so incredibly sick of this fucking thread. We've had enough legacy farts coming out of the woodwork advertising their own massive experience and cluelessness by now. Both hpa and alan are in this thread and everyone else can be ignored on the issue. Over the course of a 100 messages or so in this thread it's been determined that the best course of action is to keep the out for ISA and replace it with udelay() for chipset logic. Now go away. Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: >> This is a timing issue, isn't it? How are we synchronising, other than >> by delaying for a (bus-dependant) period? The characteristics of each >> bus are known so a number can be assigned for "one bus cycle", without >> having to use the bus. >> > > The characteristics of the bus are not known. It could be anything > between 6 and about 16MHz. In the early days of clone PCs, as you know but perhaps many on this list might not, the bus speed could be changed, but this was user-selectable. For such a machine, delay values can be pre-calculated for each bus speed, and a kernel parameter set accordingly. Or are you saying that the characteristics of the bus on a given machine vary for reasons other than user selection? The fact that busses run at different speeds on different machines is not a problem because the delay value can be determined for each given machine. The question is, for a given machine, can we determine a delay value instead of using a junk I/O? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> This is a timing issue, isn't it? How are we synchronising, other than > by delaying for a (bus-dependant) period? The characteristics of each > bus are known so a number can be assigned for "one bus cycle", without > having to use the bus. The characteristics of the bus are not known. It could be anything between 6 and about 16MHz. The way you read the bus clock is system dependant. The underlying problem is really that over time some of the hardware has moved from the ISA world into the chipsets. That is why I sent Ingo the patches for inb_pit/inb_pic and to split ISA 8390 and non ISA 8390 support. Someone has to tackle the CMOS but we are then in a position to relegant port 0x80 timing use to ISA systems where it is fine. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
This is a timing issue, isn't it? How are we synchronising, other than by delaying for a (bus-dependant) period? The characteristics of each bus are known so a number can be assigned for one bus cycle, without having to use the bus. The characteristics of the bus are not known. It could be anything between 6 and about 16MHz. The way you read the bus clock is system dependant. The underlying problem is really that over time some of the hardware has moved from the ISA world into the chipsets. That is why I sent Ingo the patches for inb_pit/inb_pic and to split ISA 8390 and non ISA 8390 support. Someone has to tackle the CMOS but we are then in a position to relegant port 0x80 timing use to ISA systems where it is fine. Alan -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: This is a timing issue, isn't it? How are we synchronising, other than by delaying for a (bus-dependant) period? The characteristics of each bus are known so a number can be assigned for one bus cycle, without having to use the bus. The characteristics of the bus are not known. It could be anything between 6 and about 16MHz. In the early days of clone PCs, as you know but perhaps many on this list might not, the bus speed could be changed, but this was user-selectable. For such a machine, delay values can be pre-calculated for each bus speed, and a kernel parameter set accordingly. Or are you saying that the characteristics of the bus on a given machine vary for reasons other than user selection? The fact that busses run at different speeds on different machines is not a problem because the delay value can be determined for each given machine. The question is, for a given machine, can we determine a delay value instead of using a junk I/O? -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 17-01-08 14:36, David Newall wrote: In the early days of clone PCs, as you know but perhaps many on this list might not I'm so incredibly sick of this fucking thread. We've had enough legacy farts coming out of the woodwork advertising their own massive experience and cluelessness by now. Both hpa and alan are in this thread and everyone else can be ignored on the issue. Over the course of a 100 messages or so in this thread it's been determined that the best course of action is to keep the out for ISA and replace it with udelay() for chipset logic. Now go away. Rene. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
In the early days of clone PCs, as you know but perhaps many on this list might not, the bus speed could be changed, but this was user-selectable. For such a machine, delay values can be pre-calculated for each bus speed, and a kernel parameter set accordingly. Or are you saying that the characteristics of the bus on a given machine vary for reasons other than user selection? They vary based on the CPU clock, the dividers from PCI to ISA on PCI based boxes, and on the ISA only ones often on the CPU speed. Unfortunately the way you control that divider or read it is chipset specific. Nor would it be reasonable to expect the end user to set it. For PC/104 systems the same applies today. The question is, for a given machine, can we determine a delay value instead of using a junk I/O? The question (for ISA peripherals) is why bother, and with the 8390 patch there are one or two dubious PCI driver users of _p left but not much else that isn't ISA or chipset logic. The question for chipset logic where it has become integrated is can we get rid of it for some devices, if not what can we use instead Alan -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene Herman wrote: Over the course of a 100 messages or so in this thread it's been determined that the best course of action is to keep the out for ISA and replace it with udelay() for chipset logic. Now go away. Rather than this incredible rudeness, why don't you direct your energy towards convincing Alan of this. He's the hold-out. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 17-01-08 22:58, David Newall wrote: Rene Herman wrote: Over the course of a 100 messages or so in this thread it's been determined that the best course of action is to keep the out for ISA and replace it with udelay() for chipset logic. Now go away. Rather than this incredible rudeness, why don't you direct your energy towards convincing Alan of this. He's the hold-out. No he isn't and that's why I'm rude -- everything needs to be repeated over and over and over again. Read the thread(s). You didn't limit your reply to chipset logic and Alan even already submitted patches to isolate the delay for the chipset logic (PIC and PIT that is) where the expectation is that a simple udelay() will suffice. We've already talked about ISA bus speed, and how it's not in a sane sense portably determinable, we've already talked about kernel parameters, about udelay and it's usefulness in early boot, about how your rude Junk I/O is exactly what is needed for some ISA devices and so on... In fact, we're blue in the face from talking about it. So say something useful or go away. Rene -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: >> If the hardware required an intermediate junk I/O, that would be a >> reason to do one, but it doesn't, does it? It requires a delay. It's >> written thus in all of the application notes. >> > > And the only instruction that is synchronized to the bus in question is > an I/O instruction. > This is a timing issue, isn't it? How are we synchronising, other than by delaying for a (bus-dependant) period? The characteristics of each bus are known so a number can be assigned for "one bus cycle", without having to use the bus. >> Wrong again. Of course one knows how long the delay should be. The bus >> speed is known. >> > > Wrong again. ISA bus speed is neither defined precisely, nor visible in a > system portable fashion. > You say, "system portable," but I think you mean, "automatically determined." We don't have to define this value automatically, if that's so hard to do. We can use a tunable kernel-parameter. > I'm so glad you have nothing better to do than troll I'm not trolling. You know this is true because many people perceive this to be a problem. I'm working on fixing it. Not all Linux problems are solvable by diving into code, and there is anecdotal evidence to believe this one has big performance considerations. I don't understand why you are opposed to even talking about it. > if you > actually wrote code I'd be worried it might get into something people > used. Speaking of writing code: I remember working on a bluetooth Oops. Lacking the hardware, I went to you for advice on how to get it before someone for testing. You never replied. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> If the hardware required an intermediate junk I/O, that would be a > reason to do one, but it doesn't, does it? It requires a delay. It's > written thus in all of the application notes. And the only instruction that is synchronized to the bus in question is an I/O instruction. > Wrong again. Of course one knows how long the delay should be. The bus > speed is known. Wrong again. ISA bus speed is neither defined precisely, nor visible in a system portable fashion. I'm so glad you have nothing better to do than troll, if you actually wrote code I'd be worried it might get into something people used. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: > On Thu, 17 Jan 2008 01:06:24 +1030 > David Newall <[EMAIL PROTECTED]> wrote: > > >> This use of port 80 (or insert some other random number) is a croc of >> hackery of the most inexperienced kind. >> > > Wrong. It's a careful designed solution used by all sorts of code for > over 15 years. > It's not careful: it's a croc. It's an ugly hack, an abuse of process, and totally unnecessary. Read my comment about delays (next). > The task to be performed is to delay for some period > > Wrong, it is for some number of bus clocks which is why I/O cycles are > used > Wrong. It's a delay. It's a delay measured in I/O cycles, but still a delay. Doing I/O to get a delay, even if the delay is intended to be measured in I/O cycles, is hackery of the most inexperienced sort. It's the sort of thing junior programmers get boxed in the ear for. There's no satisfactory reason to do it that way. If the hardware required an intermediate junk I/O, that would be a reason to do one, but it doesn't, does it? It requires a delay. It's written thus in all of the application notes. >> that an OUT is used because you don't know how long the delay should be >> on any specific machine. What rubbish. >> > > Wrong again. > Wrong again. Of course one knows how long the delay should be. The bus speed is known. The specifications of the hardware is known. Do the math you (the programmer writing the driver, not Alan) lazy sluggard, and use a delay. It baffles commonsense to say you don't know how long it should be. >> I won't even mention the many instances of these delays where no delay >> is what properly is needed. Performance? Who cares about performance? >> > > Correctness, who needs correctness ? Well, frankly, the development process could stand a little more of it. The sooner we stop denying that this is a hack, the sooner we can fix it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Thu, 17 Jan 2008 01:06:24 +1030 David Newall <[EMAIL PROTECTED]> wrote: > This use of port 80 (or insert some other random number) is a croc of > hackery of the most inexperienced kind. Wrong. It's a careful designed solution used by all sorts of code for over 15 years. The task to be performed is to delay for some period Wrong, it is for some number of bus clocks which is why I/O cycles are used > that an OUT is used because you don't know how long the delay should be > on any specific machine. What rubbish. Wrong again. > I won't even mention the many instances of these delays where no delay > is what properly is needed. Performance? Who cares about performance? Correctness, who needs correctness ? Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David P. Reed wrote: > I think we probably have a great shot at getting Intel, Microsoft, HP, > et al.. to add a feature for Linux to one of the ACPI table > specifications that define an "unused port for delay purposes" field > in the ACPI 4.0 spec, and retrofit it into PC/104 machine BIOSes. At > least Microsoft doesn't have a patent on using port 80 for delay > purposes. :-) This use of port 80 (or insert some other random number) is a croc of hackery of the most inexperienced kind. The task to be performed is to delay for some period, and I think it's a mix of bloody mindedness and fear of unfamiliar code and specification that explains why a delay is not being coded. Lest we forget, someone who should know better said that an OUT is used because you don't know how long the delay should be on any specific machine. What rubbish. For what it's worth, I would oppose any attempt to ammend ACPI specifications in the way described above. It's bad enough to have that embarrassing and unseemly hack in Linux. It would be so much worse to enshrine the practice as industry standard practice. I won't even mention the many instances of these delays where no delay is what properly is needed. Performance? Who cares about performance? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David P. Reed wrote: I think we probably have a great shot at getting Intel, Microsoft, HP, et al.. to add a feature for Linux to one of the ACPI table specifications that define an unused port for delay purposes field in the ACPI 4.0 spec, and retrofit it into PC/104 machine BIOSes. At least Microsoft doesn't have a patent on using port 80 for delay purposes. :-) This use of port 80 (or insert some other random number) is a croc of hackery of the most inexperienced kind. The task to be performed is to delay for some period, and I think it's a mix of bloody mindedness and fear of unfamiliar code and specification that explains why a delay is not being coded. Lest we forget, someone who should know better said that an OUT is used because you don't know how long the delay should be on any specific machine. What rubbish. For what it's worth, I would oppose any attempt to ammend ACPI specifications in the way described above. It's bad enough to have that embarrassing and unseemly hack in Linux. It would be so much worse to enshrine the practice as industry standard practice. I won't even mention the many instances of these delays where no delay is what properly is needed. Performance? Who cares about performance? -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Thu, 17 Jan 2008 01:06:24 +1030 David Newall [EMAIL PROTECTED] wrote: This use of port 80 (or insert some other random number) is a croc of hackery of the most inexperienced kind. Wrong. It's a careful designed solution used by all sorts of code for over 15 years. The task to be performed is to delay for some period Wrong, it is for some number of bus clocks which is why I/O cycles are used that an OUT is used because you don't know how long the delay should be on any specific machine. What rubbish. Wrong again. I won't even mention the many instances of these delays where no delay is what properly is needed. Performance? Who cares about performance? Correctness, who needs correctness ? Alan -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: On Thu, 17 Jan 2008 01:06:24 +1030 David Newall [EMAIL PROTECTED] wrote: This use of port 80 (or insert some other random number) is a croc of hackery of the most inexperienced kind. Wrong. It's a careful designed solution used by all sorts of code for over 15 years. It's not careful: it's a croc. It's an ugly hack, an abuse of process, and totally unnecessary. Read my comment about delays (next). The task to be performed is to delay for some period Wrong, it is for some number of bus clocks which is why I/O cycles are used Wrong. It's a delay. It's a delay measured in I/O cycles, but still a delay. Doing I/O to get a delay, even if the delay is intended to be measured in I/O cycles, is hackery of the most inexperienced sort. It's the sort of thing junior programmers get boxed in the ear for. There's no satisfactory reason to do it that way. If the hardware required an intermediate junk I/O, that would be a reason to do one, but it doesn't, does it? It requires a delay. It's written thus in all of the application notes. that an OUT is used because you don't know how long the delay should be on any specific machine. What rubbish. Wrong again. Wrong again. Of course one knows how long the delay should be. The bus speed is known. The specifications of the hardware is known. Do the math you (the programmer writing the driver, not Alan) lazy sluggard, and use a delay. It baffles commonsense to say you don't know how long it should be. I won't even mention the many instances of these delays where no delay is what properly is needed. Performance? Who cares about performance? Correctness, who needs correctness ? Well, frankly, the development process could stand a little more of it. The sooner we stop denying that this is a hack, the sooner we can fix it. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
If the hardware required an intermediate junk I/O, that would be a reason to do one, but it doesn't, does it? It requires a delay. It's written thus in all of the application notes. And the only instruction that is synchronized to the bus in question is an I/O instruction. Wrong again. Of course one knows how long the delay should be. The bus speed is known. Wrong again. ISA bus speed is neither defined precisely, nor visible in a system portable fashion. I'm so glad you have nothing better to do than troll, if you actually wrote code I'd be worried it might get into something people used. Alan -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: If the hardware required an intermediate junk I/O, that would be a reason to do one, but it doesn't, does it? It requires a delay. It's written thus in all of the application notes. And the only instruction that is synchronized to the bus in question is an I/O instruction. This is a timing issue, isn't it? How are we synchronising, other than by delaying for a (bus-dependant) period? The characteristics of each bus are known so a number can be assigned for one bus cycle, without having to use the bus. Wrong again. Of course one knows how long the delay should be. The bus speed is known. Wrong again. ISA bus speed is neither defined precisely, nor visible in a system portable fashion. You say, system portable, but I think you mean, automatically determined. We don't have to define this value automatically, if that's so hard to do. We can use a tunable kernel-parameter. I'm so glad you have nothing better to do than troll I'm not trolling. You know this is true because many people perceive this to be a problem. I'm working on fixing it. Not all Linux problems are solvable by diving into code, and there is anecdotal evidence to believe this one has big performance considerations. I don't understand why you are opposed to even talking about it. if you actually wrote code I'd be worried it might get into something people used. Speaking of writing code: I remember working on a bluetooth Oops. Lacking the hardware, I went to you for advice on how to get it before someone for testing. You never replied. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David Woodhouse wrote: On Fri, 2008-01-11 at 09:35 -0500, David P. Reed wrote: Using any "unused port" for a delay means that the machine check feature is wasted and utterly unusable. Not entirely unusable. You can recover silently from the machine check if it was one of the known accesses to the 'unused port'. It certainly achieves a delay :) I'm sure that's what the driver writers had in mind. ;-) And I think we probably have a great shot at getting Intel, Microsoft, HP, et al.. to add a feature for Linux to one of the ACPI table specifications that define an "unused port for delay purposes" field in the ACPI 4.0 spec, and retrofit it into PC/104 machine BIOSes. At least Microsoft doesn't have a patent on using port 80 for delay purposes. :-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Fri, 2008-01-11 at 09:35 -0500, David P. Reed wrote: > Using any "unused port" for a delay means that the machine check > feature is wasted and utterly unusable. Not entirely unusable. You can recover silently from the machine check if it was one of the known accesses to the 'unused port'. It certainly achieves a delay :) On ppc32 we recover from the machine check if it was any inb/outb -- mostly to work around crappy drivers developed on i386, I believe. -- dwmw2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Fri, 2008-01-11 at 09:35 -0500, David P. Reed wrote: Using any unused port for a delay means that the machine check feature is wasted and utterly unusable. Not entirely unusable. You can recover silently from the machine check if it was one of the known accesses to the 'unused port'. It certainly achieves a delay :) On ppc32 we recover from the machine check if it was any inb/outb -- mostly to work around crappy drivers developed on i386, I believe. -- dwmw2 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David Woodhouse wrote: On Fri, 2008-01-11 at 09:35 -0500, David P. Reed wrote: Using any unused port for a delay means that the machine check feature is wasted and utterly unusable. Not entirely unusable. You can recover silently from the machine check if it was one of the known accesses to the 'unused port'. It certainly achieves a delay :) I'm sure that's what the driver writers had in mind. ;-) And I think we probably have a great shot at getting Intel, Microsoft, HP, et al.. to add a feature for Linux to one of the ACPI table specifications that define an unused port for delay purposes field in the ACPI 4.0 spec, and retrofit it into PC/104 machine BIOSes. At least Microsoft doesn't have a patent on using port 80 for delay purposes. :-) -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David P. Reed wrote: Alan Cox wrote: bus abort on the LPC bus". More problematic is that I would think some people might want to turn on the AMD feature that generates machine checks if a bus timeout happens. The whole point of machine checks is An ISA/LPC bus timeout is fulfilled by the bridge so doesn't cause an MCE. Good possibility, but the documentation on HyperTransport suggests otherwise, even for LPC bridges in this particular modern world of AMD64. I might do the experiment someday to see if my LPC bridge is implemented in a way that does or doesn't support enabling MCE's. Could be different between Intel and AMD - I haven't had reason to pore over the Intel chipset specs, since my poking into all this stuff has been driven by my personal machine's issues, and it's not got any Intel compatible parts. If you have a subtractive decoding bridge you will have completion on HT. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: bus abort on the LPC bus". More problematic is that I would think some people might want to turn on the AMD feature that generates machine checks if a bus timeout happens. The whole point of machine checks is An ISA/LPC bus timeout is fulfilled by the bridge so doesn't cause an MCE. Good possibility, but the documentation on HyperTransport suggests otherwise, even for LPC bridges in this particular modern world of AMD64. I might do the experiment someday to see if my LPC bridge is implemented in a way that does or doesn't support enabling MCE's. Could be different between Intel and AMD - I haven't had reason to pore over the Intel chipset specs, since my poking into all this stuff has been driven by my personal machine's issues, and it's not got any Intel compatible parts. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 11-01-08 15:35, David P. Reed wrote: Rene Herman wrote: On 11-01-08 02:36, Zachary Amsden wrote: FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Might not give you a "proper" delay though. 0xed should be a better choice... I don't think there is any magic here. Golly, you don't think so? Just commenting on his local hack. Port 0x84 is inside the (reserved) DMA page register range and stands a better chance of not being echoed onto ISA by various chipsets than 0xed does due to that. Yes -- on a sane machine it's all useless anyway and with all sane machines this discussion would've ended quite some time ago already. It's the insane, obsolete legacy junk that's the problem. Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> bus abort on the LPC bus". More problematic is that I would think some > people might want to turn on the AMD feature that generates machine > checks if a bus timeout happens. The whole point of machine checks is An ISA/LPC bus timeout is fulfilled by the bridge so doesn't cause an MCE. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene Herman wrote: On 11-01-08 02:36, Zachary Amsden wrote: FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Might not give you a "proper" delay though. 0xed should be a better choice... I don't think there is any magic here. I modified the patch to do *no delay at all* in the io_delay "quirk" and have been running reliably for weeks including the very heavy I/O load that comes from using software RAID on this nice laptop that has two separate SATA drives! This particular laptop has no problematic devices - the only problem is actually in the CMOS_READ and CMOS_WRITE macros that *use* the _p operations in a way that is unnecessary on this machine. (in fact, it would be hard to add a problematic device - there's no PCMCIA slot either, and so every option is USB or Firewire). Using 0xED happens to work, but it's not guaranteed to work either. There is not a "standard" for an "unused port that is mapped to cause a bus abort on the LPC bus". More problematic is that I would think some people might want to turn on the AMD feature that generates machine checks if a bus timeout happens. The whole point of machine checks is to allow the machine to be more reliable. Using any "unused port" for a delay means that the machine check feature is wasted and utterly unusable. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 11-01-08 15:35, David P. Reed wrote: Rene Herman wrote: On 11-01-08 02:36, Zachary Amsden wrote: FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Might not give you a proper delay though. 0xed should be a better choice... I don't think there is any magic here. Golly, you don't think so? Just commenting on his local hack. Port 0x84 is inside the (reserved) DMA page register range and stands a better chance of not being echoed onto ISA by various chipsets than 0xed does due to that. Yes -- on a sane machine it's all useless anyway and with all sane machines this discussion would've ended quite some time ago already. It's the insane, obsolete legacy junk that's the problem. Rene. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
bus abort on the LPC bus. More problematic is that I would think some people might want to turn on the AMD feature that generates machine checks if a bus timeout happens. The whole point of machine checks is An ISA/LPC bus timeout is fulfilled by the bridge so doesn't cause an MCE. Alan -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene Herman wrote: On 11-01-08 02:36, Zachary Amsden wrote: FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Might not give you a proper delay though. 0xed should be a better choice... I don't think there is any magic here. I modified the patch to do *no delay at all* in the io_delay quirk and have been running reliably for weeks including the very heavy I/O load that comes from using software RAID on this nice laptop that has two separate SATA drives! This particular laptop has no problematic devices - the only problem is actually in the CMOS_READ and CMOS_WRITE macros that *use* the _p operations in a way that is unnecessary on this machine. (in fact, it would be hard to add a problematic device - there's no PCMCIA slot either, and so every option is USB or Firewire). Using 0xED happens to work, but it's not guaranteed to work either. There is not a standard for an unused port that is mapped to cause a bus abort on the LPC bus. More problematic is that I would think some people might want to turn on the AMD feature that generates machine checks if a bus timeout happens. The whole point of machine checks is to allow the machine to be more reliable. Using any unused port for a delay means that the machine check feature is wasted and utterly unusable. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: bus abort on the LPC bus. More problematic is that I would think some people might want to turn on the AMD feature that generates machine checks if a bus timeout happens. The whole point of machine checks is An ISA/LPC bus timeout is fulfilled by the bridge so doesn't cause an MCE. Good possibility, but the documentation on HyperTransport suggests otherwise, even for LPC bridges in this particular modern world of AMD64. I might do the experiment someday to see if my LPC bridge is implemented in a way that does or doesn't support enabling MCE's. Could be different between Intel and AMD - I haven't had reason to pore over the Intel chipset specs, since my poking into all this stuff has been driven by my personal machine's issues, and it's not got any Intel compatible parts. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David P. Reed wrote: Alan Cox wrote: bus abort on the LPC bus. More problematic is that I would think some people might want to turn on the AMD feature that generates machine checks if a bus timeout happens. The whole point of machine checks is An ISA/LPC bus timeout is fulfilled by the bridge so doesn't cause an MCE. Good possibility, but the documentation on HyperTransport suggests otherwise, even for LPC bridges in this particular modern world of AMD64. I might do the experiment someday to see if my LPC bridge is implemented in a way that does or doesn't support enabling MCE's. Could be different between Intel and AMD - I haven't had reason to pore over the Intel chipset specs, since my poking into all this stuff has been driven by my personal machine's issues, and it's not got any Intel compatible parts. If you have a subtractive decoding bridge you will have completion on HT. -hpa -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 11-01-08 02:36, Zachary Amsden wrote: FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Might not give you a "proper" delay though. 0xed should be a better choice... Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, 2008-01-09 at 17:22 -0500, David P. Reed wrote: > Zachary Amsden wrote: > > > > According to Phoenix Technologies book "System BIOS for IBM PCs, > > Compatibles and EISA Computers, 2nd Edition", the I/O port list gives > > > > port 0080h R/W Extra page register (temporary storage) > > > > Despite looking, I've never seen it documented anywhere else, but I > > believe it works on just about every PC platform. Except, apparently, > > my laptop. > > > > > > > The port 80 problem was discovered by me, after months of "bisecting" > the running code around a problem with hanging when using hwclock in > 64-bit mode when ACPI is on. So it kills my laptop, too, and many > currentlaptop motherboards designed by Quanta for HP and Compaq (dv6000, > dv9000, tx1000, apparently) Thanks very much for that - I was debugging this for a while too, and eventually just shut off hwclock. > Your laptop isn't an aberration. It's part of the new generation of > evolved machines that take advantage of the capabilities of ACPI and > SMBIOS and DMI standards that are becoming core parts of the market. I beg to differ. I managed to turn the thing into a brick by upgrading the BIOS (with the correct image, no less) in an attempt to fix it. I just got it back from repair. I'm not sure that is positive evolutionary development, but it certainly does make my laptop an aberration :) FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Zach -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene Herman wrote: On 10-01-08 01:37, Robert Hancock wrote: I agree. In this case the BIOS on these laptops is trying to tell us "port 80 is used for our purposes, do not touch it". We should be listening. Listening is fine but what are you going to do after you have listened? Right, not use port 0x80 but since that's the current idea anyway outside of legacy drivers, you don't actually need to listen. If the quirk-to-0xed or similar was to stay, it's a much better switching point than DMI strings but if not, it's not actually important. Well, I was just suggesting a warning that would come up when a driver that still used port 80 was initialized... I think that is what Alan Cox and others suggest for legacy drivers that have worked - I agree that it may not be the right thing to screw them up, especially since my laptop, and probably most machines that might start using port 80 or other "legacy ports" won't ever need those drivers. I thought more about a complete solution last night. A clean idea that really fits the linux design might be the following outline of a patch. I suspect it might seem far less ugly, and probably would meet Alan Cox's needs, too - I am very sympathetic about not breaking 8390's, etc. Define a "motherboard resources" driver that claims all the resources defined for PNP0C02 devices during the pnp process. I think Windoze actually does something quite similar. This would claim port 80. Define an iodelay driver. This driver exists largely to claim port 80 for the iodelay operation (you could even define an option for other ports). Legacy drivers would be modified to require iodelay. The iodelay driver would set up the iodelay mechanism to do something other than the "boot time" default - which could be no delay, or udelay. It would also set a flag that says "_b operations are safe". Put a WARN_ONCE() in the in/out*_b operations that checks the flag that is set by the iodelay driver. This would only trigger in the case that 80 or whatever was reserved by some other device driver - such as the motherboard resources driver above. Modern machines won't do that. Finally, anything that happens before the motherboard resources and iodelay drivers are initialized cannot use in*_p or out*_p (whether they can be loadable modules rather than built in is a question). This is a very small set, and I believe with the exception of the PIT (8253/4) are very safe. Note that this idea is also compatible with rewriting all drivers to use "iodelay()" explicitly instead of _p(). But it doesn't require that. Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Rene Herman wrote: On 10-01-08 01:37, Robert Hancock wrote: I agree. In this case the BIOS on these laptops is trying to tell us port 80 is used for our purposes, do not touch it. We should be listening. Listening is fine but what are you going to do after you have listened? Right, not use port 0x80 but since that's the current idea anyway outside of legacy drivers, you don't actually need to listen. If the quirk-to-0xed or similar was to stay, it's a much better switching point than DMI strings but if not, it's not actually important. Well, I was just suggesting a warning that would come up when a driver that still used port 80 was initialized... I think that is what Alan Cox and others suggest for legacy drivers that have worked - I agree that it may not be the right thing to screw them up, especially since my laptop, and probably most machines that might start using port 80 or other legacy ports won't ever need those drivers. I thought more about a complete solution last night. A clean idea that really fits the linux design might be the following outline of a patch. I suspect it might seem far less ugly, and probably would meet Alan Cox's needs, too - I am very sympathetic about not breaking 8390's, etc. Define a motherboard resources driver that claims all the resources defined for PNP0C02 devices during the pnp process. I think Windoze actually does something quite similar. This would claim port 80. Define an iodelay driver. This driver exists largely to claim port 80 for the iodelay operation (you could even define an option for other ports). Legacy drivers would be modified to require iodelay. The iodelay driver would set up the iodelay mechanism to do something other than the boot time default - which could be no delay, or udelay. It would also set a flag that says _b operations are safe. Put a WARN_ONCE() in the in/out*_b operations that checks the flag that is set by the iodelay driver. This would only trigger in the case that 80 or whatever was reserved by some other device driver - such as the motherboard resources driver above. Modern machines won't do that. Finally, anything that happens before the motherboard resources and iodelay drivers are initialized cannot use in*_p or out*_p (whether they can be loadable modules rather than built in is a question). This is a very small set, and I believe with the exception of the PIT (8253/4) are very safe. Note that this idea is also compatible with rewriting all drivers to use iodelay() explicitly instead of _p(). But it doesn't require that. Rene. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, 2008-01-09 at 17:22 -0500, David P. Reed wrote: Zachary Amsden wrote: According to Phoenix Technologies book System BIOS for IBM PCs, Compatibles and EISA Computers, 2nd Edition, the I/O port list gives port 0080h R/W Extra page register (temporary storage) Despite looking, I've never seen it documented anywhere else, but I believe it works on just about every PC platform. Except, apparently, my laptop. The port 80 problem was discovered by me, after months of bisecting the running code around a problem with hanging when using hwclock in 64-bit mode when ACPI is on. So it kills my laptop, too, and many currentlaptop motherboards designed by Quanta for HP and Compaq (dv6000, dv9000, tx1000, apparently) Thanks very much for that - I was debugging this for a while too, and eventually just shut off hwclock. Your laptop isn't an aberration. It's part of the new generation of evolved machines that take advantage of the capabilities of ACPI and SMBIOS and DMI standards that are becoming core parts of the market. I beg to differ. I managed to turn the thing into a brick by upgrading the BIOS (with the correct image, no less) in an attempt to fix it. I just got it back from repair. I'm not sure that is positive evolutionary development, but it certainly does make my laptop an aberration :) FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Zach -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 11-01-08 02:36, Zachary Amsden wrote: FWIW, I fixed the problem locally by recompiling, changing port 80 to port 84 in io.h; works great, and doesn't conflict with any occupied ports. Might not give you a proper delay though. 0xed should be a better choice... Rene. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 10-01-08 01:37, Robert Hancock wrote: David P. Reed wrote: I have a small suggestion in mind that might be helpful in the future: the "motherboard resources" discovered as PNP0C02 devices in their _CRS settings in ACPI during ACPI PnP startup should be reserved (or checked), and any drivers that still use port 80 implicitly should reserve that port. I agree. In this case the BIOS on these laptops is trying to tell us "port 80 is used for our purposes, do not touch it". We should be listening. Listening is fine but what are you going to do after you have listened? Right, not use port 0x80 but since that's the current idea anyway outside of legacy drivers, you don't actually need to listen. If the quirk-to-0xed or similar was to stay, it's a much better switching point than DMI strings but if not, it's not actually important. Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David P. Reed wrote: Christer Weinigel wrote: Did I miss anyting? Nothing that seems *crucial* going forward for Linux. The fate of "legacy machines" is really important to get right. I have a small suggestion in mind that might be helpful in the future: the "motherboard resources" discovered as PNP0C02 devices in their _CRS settings in ACPI during ACPI PnP startup should be reserved (or checked), and any drivers that still use port 80 implicitly should reserve that port. I agree. In this case the BIOS on these laptops is trying to tell us "port 80 is used for our purposes, do not touch it". We should be listening. -- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from [EMAIL PROTECTED] Home Page: http://www.roberthancock.com/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Zachary Amsden wrote: According to Phoenix Technologies book "System BIOS for IBM PCs, Compatibles and EISA Computers, 2nd Edition", the I/O port list gives port 0080h R/W Extra page register (temporary storage) Despite looking, I've never seen it documented anywhere else, but I believe it works on just about every PC platform. Except, apparently, my laptop. The port 80 problem was discovered by me, after months of "bisecting" the running code around a problem with hanging when using hwclock in 64-bit mode when ACPI is on. So it kills my laptop, too, and many currentlaptop motherboards designed by Quanta for HP and Compaq (dv6000, dv9000, tx1000, apparently) In the last couple of weeks, I was able with luck to discover that the problem is the ENE KB3920 chip, which is the "big brother" of the KB3700 chip included in the OLPC XO "$100 laptop" made also by Quanta. I verified this by taking my laptop apart - a fun and risky experience. Didn't break any connectors, but I don't recommend it for those who are not experienced disassembling laptops and cellphones, etc. The KB3920 contains an EC, an SMBus, a KBC, some watchdog timers, and a variety of other functions that keep the laptop going, coordinating the relationships among various peripherals. The firmware is part standard from ENE, part OEM-specific, in this case coded by Quanta or a BIOS subcontractor. You can read the specsheet for the KB3700 online at laptop.org, since the specs of the laptop are "open". The 3920's spec is confidential. And the firmware is confidential as well for both the 3700 and 3920. Clues as to what it does can be gleaned by reading the disassembler output of the DSDT code in the particular laptops - though the SMM BIOS probably also talks to it. Modern machines have many subsystems, and the ACPI and SMBIOS coordinate to run them; blade servers also have drawer controllers and backplane management buses. The part that runs Linux is only part of the machine. Your laptop isn't an aberration. It's part of the new generation of evolved machines that take advantage of the capabilities of ACPI and SMBIOS and DMI standards that are becoming core parts of the market. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Christer Weinigel wrote: On Wed, 09 Jan 2008 10:18:11 -0800 "H. Peter Anvin" <[EMAIL PROTECTED]> wrote: Zachary Amsden wrote: I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? Why should the bitsize of the CPU matter for this? It seems one of the less meaningful keys for this. Well, anything that runs x86_64 should be a fairly modern system. Yes, but you hardly want a situation where the machine works booting a 32-bit kernel and not a 64-bit kernel, or vice versa. Furthermore, it's not so much about "modern" versus "old", it is about picking a certain set of bugs. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 2008-01-08 at 21:19 -0800, H. Peter Anvin wrote: > Zachary Amsden wrote: > > > > BTW, it isn't ever safe to pass port 0x80 through to hardware from a > > virtual machine; some OSes use port 0x80 as a hardware available scratch > > register (I believe Darwin/x86 did/does this during boot). > > That's funny, because there is definitely no guarantee that you get back > what you read (well, perhaps there is on Apple.) According to Phoenix Technologies book "System BIOS for IBM PCs, Compatibles and EISA Computers, 2nd Edition", the I/O port list gives port 0080h R/W Extra page register (temporary storage) Despite looking, I've never seen it documented anywhere else, but I believe it works on just about every PC platform. Except, apparently, my laptop. Zach -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Hi, David P. Reed reed.com> writes: > And actually, if I had looked at the /sys/bus/pnp definitions, rather > than /proc/ioports, I would have noticed that port 80 was part of a > PNP0C02 resource set. That means exactly one thing: ACPI says that > port 80 is NOT free to be used, for delays or anything else. I have some computers where port 0x80 is claimed by 8237A DMA controller [1] But in this case it seems a lasy acpi programmer that doesn't want to convert the hole in 0x80-0x8f range... PS : I post from gmane web interface, so I can't keep CC. [1] This happen with a old 7 years old siemens PIII and a new hp core2duo. state = active io 0x0-0xf io 0x80-0x8f io 0xc0-0xdf dma 4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, 09 Jan 2008 10:18:11 -0800 "H. Peter Anvin" <[EMAIL PROTECTED]> wrote: > Zachary Amsden wrote: > > > > I'm speaking specifically in terms of 64-bit platforms here. > > Shouldn't we unconditionally drop outb_p doing extra port I/O on > > 64-bit architectures? Especially considering they don't even have > > an ISA bus where the decode timing could even matter? > > > > Why should the bitsize of the CPU matter for this? It seems one of > the less meaningful keys for this. Well, anything that runs x86_64 should be a fairly modern system. > Second, as I have mentioned, I don't believe this is really the case, > especially not for the PIT, which is still present -- the PIT > *semantics* has explicit timing constraints. > > Third, you still have ISA devices, they're just called LPC or PC104 > devices these days. Or PCMCIA. I'm still a happy user of a Zyxel ZyAIR 100B, it's one of the most stable cards Wifi I've got running under Linux. :-) /Christer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Adrian Bunk wrote: I don't think the latter statement was true - AFAIR there are Alphas with ISA slots. See subject line. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, Jan 09, 2008 at 10:17:24AM -0800, Zachary Amsden wrote: > On Wed, 2008-01-09 at 16:27 +0100, Rene Herman wrote: > > On 09-01-08 06:30, Christer Weinigel wrote: > > I'd not expect very time crtical. The current outb_p use gives a delay > > somewhere between .5 and 2 microseconds as per earlier survey meaning a > > udelay(1) or 2 would be enough -- again, at the point that udelay() is > > sensible. > > > > New machines don't use the legacy PIC anymore anyway. > > > > > The floppy controller code uses outb_p. Even though there might be > > > floppy controllers on modern systems, I'd rather leave the floppy code > > > alone since it's supposed to be very fragile. If you still use > > > floppies you deserve what you get. > > > > Floppies forever. In practice, leaving it alone isn't going to matter, but > > in that same practice changing it to udelay() probably doesn't either. The > > ones to leave alone are the ones that are clumsy/impossible to test and the > > ones such as in NIC drivers that were specifically tuned. > > I'm speaking specifically in terms of 64-bit platforms here. Shouldn't > we unconditionally drop outb_p doing extra port I/O on 64-bit > architectures? Especially considering they don't even have an ISA bus > where the decode timing could even matter? >... I don't think the latter statement was true - AFAIR there are Alphas with ISA slots. > Agree. > > Zach cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Maciej W. Rozycki wrote: On Tue, 1 Jan 2008, H. Peter Anvin wrote: It's specifically a side effect *we don't care about*, except in the by-now-somewhat-exotic case of 386+387 (where we indeed can't use it once user code has touched the FPU -- but we can fall back to 0x80 on those, a very small number of systems.) 486+ doesn't use this interface under Linux, since Linux uses the proper exception path on those processors. If Compaq had wired up the proper signals on the first 386 PC motherboards, we wouldn't have cared about it on the 386 either. It was actually IBM who broke it with the 80286-based PC/AT because of the BIOS compatibility -- the vector #0x10 had already been claimed by the original PC for the video software interrupt call (apparently against Intel's recommendation not to use low 32 interrupt vectors for such purposes), so it could not have been reused as is for FP exception handling without breaking existing software. I suppose a more complicated piece of glue logic could have been used along the lines of what eventually went into the i486, but presumably the relatively low level of integration of the PC/AT made such additional circuits hard to justify even if it indeed was considered. Supposedly the reason was that the DOS-less "cassette BASIC" delivered by Microsoft used all the INT instructions except the reserved ones as a weird bytecode interpreter. Bill Gates was fond of that kind of hacks. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Zachary Amsden wrote: I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? Why should the bitsize of the CPU matter for this? It seems one of the less meaningful keys for this. Second, as I have mentioned, I don't believe this is really the case, especially not for the PIT, which is still present -- the PIT *semantics* has explicit timing constraints. Third, you still have ISA devices, they're just called LPC or PC104 devices these days. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, 2008-01-09 at 16:27 +0100, Rene Herman wrote: > On 09-01-08 06:30, Christer Weinigel wrote: > I'd not expect very time crtical. The current outb_p use gives a delay > somewhere between .5 and 2 microseconds as per earlier survey meaning a > udelay(1) or 2 would be enough -- again, at the point that udelay() is > sensible. > > New machines don't use the legacy PIC anymore anyway. > > > The floppy controller code uses outb_p. Even though there might be > > floppy controllers on modern systems, I'd rather leave the floppy code > > alone since it's supposed to be very fragile. If you still use > > floppies you deserve what you get. > > Floppies forever. In practice, leaving it alone isn't going to matter, but > in that same practice changing it to udelay() probably doesn't either. The > ones to leave alone are the ones that are clumsy/impossible to test and the > ones such as in NIC drivers that were specifically tuned. I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? > If simple outb_p() deprecation is considered enough instead, no need to > touch anything in drivers/, only changes to "outb(); udelay()" outside > drivers/. > > I'd let Alan decide here. Agree. Zach -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 1 Jan 2008, H. Peter Anvin wrote: > It's specifically a side effect *we don't care about*, except in the > by-now-somewhat-exotic case of 386+387 (where we indeed can't use it once user > code has touched the FPU -- but we can fall back to 0x80 on those, a very > small number of systems.) 486+ doesn't use this interface under Linux, since > Linux uses the proper exception path on those processors. If Compaq had wired > up the proper signals on the first 386 PC motherboards, we wouldn't have cared > about it on the 386 either. It was actually IBM who broke it with the 80286-based PC/AT because of the BIOS compatibility -- the vector #0x10 had already been claimed by the original PC for the video software interrupt call (apparently against Intel's recommendation not to use low 32 interrupt vectors for such purposes), so it could not have been reused as is for FP exception handling without breaking existing software. I suppose a more complicated piece of glue logic could have been used along the lines of what eventually went into the i486, but presumably the relatively low level of integration of the PC/AT made such additional circuits hard to justify even if it indeed was considered. Maciej -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 09-01-08 06:30, Christer Weinigel wrote: On Tue, 08 Jan 2008 18:52:42 -0800 Zachary Amsden <[EMAIL PROTECTED]> wrote: What is the outcome of this thread? Are we going to use timing based port delays, or can we finally drop these things entirely on 64-bit architectures? I a have a doubly vested interest in this, both as the owner of an affected HP dv9210us laptop and as a maintainer of paravirt code - and would like 64-bit Linux code to stop using I/O to port 0x80 in both cases (as I suspect would every other person involved with virtualization). I've tried to follow this thread, but with all the jabs, 1-ups, and obscure legacy hardware pageantry going on, it isn't clear what we're really doing. I belive Alan Cox is doing a review of some drivers, to see if they actually need the I/O port delay. A lot of drivers probably use outb_p just because it was copy-pasted from some other driver and it can be removed. Alan's review has also brought to light a lack of locking in some drivers, so I think Alan has been adding proper locking to some of the watchdog drivers. Yes, Alan should be considered to be in the driver seat here (and current x86.git changes should be tossed). Most old ISA only device drivers can keep using OUT 80h. They are not used on modern machines and it's better to keep them unchanged to avoid unneccesary incompatibilities. As far as I know, the 8253 PIT timer code needs outb_p on some older platform, and this is one of the most troublesome since the same PIT controller (or a register compatible one) has been used since the original IBM PC, and it is frequently executed code. Ingo Molnar has done an alternate implementation of the PIT clock source which uses udelay instead of OUT 80h to delay accesses to the ports. The kernel could make a choice of which variant to use based on the DMI year, if compiling for x86_64, or something similar. Maybe have a command line option too. Just udelay() should be fine after "fixing" udelay() to be somewhat usefully defined pre-calibration. The keyboard controller on some platform needs the delay, and the same driver is used on both ancient and modern systems, I think it can be changed to udelay since it's not so time critical code. The 8259 interrupt controller on some platform needs the delay, I think it can be changed to udelay since it's only some setup code that uses outb_p. I guess there are time critical accesses to the interrupt controller from assembly code somewhere to acknowledge interrupts, and that code needs a review. I'd not expect very time crtical. The current outb_p use gives a delay somewhere between .5 and 2 microseconds as per earlier survey meaning a udelay(1) or 2 would be enough -- again, at the point that udelay() is sensible. New machines don't use the legacy PIC anymore anyway. The floppy controller code uses outb_p. Even though there might be floppy controllers on modern systems, I'd rather leave the floppy code alone since it's supposed to be very fragile. If you still use floppies you deserve what you get. Floppies forever. In practice, leaving it alone isn't going to matter, but in that same practice changing it to udelay() probably doesn't either. The ones to leave alone are the ones that are clumsy/impossible to test and the ones such as in NIC drivers that were specifically tuned. Some specific drivers, such as drivers for 8390 or 8390 clone based network cards are also a bit troublesome, they do need outb_p (and the delay for the original 8390 chip is specified in bus cycles), and there can be a big performance loss if pessimistic udelays are used for the delay. There are still a bunch of PCMCIA cards based on that chip which means that those cards can be used with modern machines. There are also PCI and memory mapped variants of the 8390, some of them new designs which are only register compatible, some other designs are using a real 8390 with a FPGA used as glue logic. I think Alan suggested compiling two versions of that driver, one with OUT 80h, and one with udelay. Old machines can choose the old driver, and new machines can use the new one. Other drivers can probably do the same thing, or if not time critical, always use a pessimistic udelay. Not sure what the final suggestion for those was either As for the implementation, I like the suggestion to split outb_b into two calls, one to outb and one to isa_slow_down_io. It makes it very obvious that it is really two function calls, and that it needs locking. For those uses that are not ISA port accesses, isa_slow_down_io should be changed to an appropriate udelay instead. ... or simply deleted. The current outb_p is "outb; slow_down_io" as a macro so that with this you also get no binary changes, making it rather easy to prove that things do not change timing in cases where you keep the delay. (they're not so much function calls though -- they're inlined). The goal is anyway that a modern machine
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Christer Weinigel wrote: Did I miss anyting? Nothing that seems *crucial* going forward for Linux. The fate of "legacy machines" is really important to get right. I have a small suggestion in mind that might be helpful in the future: the "motherboard resources" discovered as PNP0C02 devices in their _CRS settings in ACPI during ACPI PnP startup should be reserved (or checked), and any drivers that still use port 80 implicitly should reserve that port. This may be too late in the boot process to make a decision not to use port 80, and it doesn't help decide a strategy to use an alternate port (0xED happens to "work" on the dv9000 machines in the sense that it generates a bus timeout on LPC, but there is no guarantee that 0xED is free on any particular motherboard, and "unusedness" is not declared in any BIOS/ACPI tables) or to use a udelay-based iodelay (but there is nothing in the BIOS tables that suggest the right delays for various I/O ports if any modern parts need them...which I question, but can't prove a negative in general). However, doing the reservations on such resources could generate a warning that would help diagnose new current and future designs including devices like the ENE KB3920 that have a port that is defaulted to port 80 and routed to the EC for functions that the firmware and ACPI can agree to do. Or any other ports used in new ways and properly notified to the OS via the now-standard Wintel BIOS functions. I don't know if /proc/ioports is being maintained, but the fact that it doesn't contain all of those PNP0C02 resources known on my machine seems to be a bug - which I am happy to code a patch or two for as a contribution back to Linux, if it isn't on the way out as the /sys hierarchy does a better job. /sys/bus/pnp/... does get built properly and has port 80 described properly - not as a DMA port, but as a port in use by device 05:00, which is the motherboard resource catchall. Thus the patch would be small. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Christer Weinigel wrote: Did I miss anyting? Nothing that seems *crucial* going forward for Linux. The fate of legacy machines is really important to get right. I have a small suggestion in mind that might be helpful in the future: the motherboard resources discovered as PNP0C02 devices in their _CRS settings in ACPI during ACPI PnP startup should be reserved (or checked), and any drivers that still use port 80 implicitly should reserve that port. This may be too late in the boot process to make a decision not to use port 80, and it doesn't help decide a strategy to use an alternate port (0xED happens to work on the dv9000 machines in the sense that it generates a bus timeout on LPC, but there is no guarantee that 0xED is free on any particular motherboard, and unusedness is not declared in any BIOS/ACPI tables) or to use a udelay-based iodelay (but there is nothing in the BIOS tables that suggest the right delays for various I/O ports if any modern parts need them...which I question, but can't prove a negative in general). However, doing the reservations on such resources could generate a warning that would help diagnose new current and future designs including devices like the ENE KB3920 that have a port that is defaulted to port 80 and routed to the EC for functions that the firmware and ACPI can agree to do. Or any other ports used in new ways and properly notified to the OS via the now-standard Wintel BIOS functions. I don't know if /proc/ioports is being maintained, but the fact that it doesn't contain all of those PNP0C02 resources known on my machine seems to be a bug - which I am happy to code a patch or two for as a contribution back to Linux, if it isn't on the way out as the /sys hierarchy does a better job. /sys/bus/pnp/... does get built properly and has port 80 described properly - not as a DMA port, but as a port in use by device 05:00, which is the motherboard resource catchall. Thus the patch would be small. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 09-01-08 06:30, Christer Weinigel wrote: On Tue, 08 Jan 2008 18:52:42 -0800 Zachary Amsden [EMAIL PROTECTED] wrote: What is the outcome of this thread? Are we going to use timing based port delays, or can we finally drop these things entirely on 64-bit architectures? I a have a doubly vested interest in this, both as the owner of an affected HP dv9210us laptop and as a maintainer of paravirt code - and would like 64-bit Linux code to stop using I/O to port 0x80 in both cases (as I suspect would every other person involved with virtualization). I've tried to follow this thread, but with all the jabs, 1-ups, and obscure legacy hardware pageantry going on, it isn't clear what we're really doing. I belive Alan Cox is doing a review of some drivers, to see if they actually need the I/O port delay. A lot of drivers probably use outb_p just because it was copy-pasted from some other driver and it can be removed. Alan's review has also brought to light a lack of locking in some drivers, so I think Alan has been adding proper locking to some of the watchdog drivers. Yes, Alan should be considered to be in the driver seat here (and current x86.git changes should be tossed). Most old ISA only device drivers can keep using OUT 80h. They are not used on modern machines and it's better to keep them unchanged to avoid unneccesary incompatibilities. As far as I know, the 8253 PIT timer code needs outb_p on some older platform, and this is one of the most troublesome since the same PIT controller (or a register compatible one) has been used since the original IBM PC, and it is frequently executed code. Ingo Molnar has done an alternate implementation of the PIT clock source which uses udelay instead of OUT 80h to delay accesses to the ports. The kernel could make a choice of which variant to use based on the DMI year, if compiling for x86_64, or something similar. Maybe have a command line option too. Just udelay() should be fine after fixing udelay() to be somewhat usefully defined pre-calibration. The keyboard controller on some platform needs the delay, and the same driver is used on both ancient and modern systems, I think it can be changed to udelay since it's not so time critical code. The 8259 interrupt controller on some platform needs the delay, I think it can be changed to udelay since it's only some setup code that uses outb_p. I guess there are time critical accesses to the interrupt controller from assembly code somewhere to acknowledge interrupts, and that code needs a review. I'd not expect very time crtical. The current outb_p use gives a delay somewhere between .5 and 2 microseconds as per earlier survey meaning a udelay(1) or 2 would be enough -- again, at the point that udelay() is sensible. New machines don't use the legacy PIC anymore anyway. The floppy controller code uses outb_p. Even though there might be floppy controllers on modern systems, I'd rather leave the floppy code alone since it's supposed to be very fragile. If you still use floppies you deserve what you get. Floppies forever. In practice, leaving it alone isn't going to matter, but in that same practice changing it to udelay() probably doesn't either. The ones to leave alone are the ones that are clumsy/impossible to test and the ones such as in NIC drivers that were specifically tuned. Some specific drivers, such as drivers for 8390 or 8390 clone based network cards are also a bit troublesome, they do need outb_p (and the delay for the original 8390 chip is specified in bus cycles), and there can be a big performance loss if pessimistic udelays are used for the delay. There are still a bunch of PCMCIA cards based on that chip which means that those cards can be used with modern machines. There are also PCI and memory mapped variants of the 8390, some of them new designs which are only register compatible, some other designs are using a real 8390 with a FPGA used as glue logic. I think Alan suggested compiling two versions of that driver, one with OUT 80h, and one with udelay. Old machines can choose the old driver, and new machines can use the new one. Other drivers can probably do the same thing, or if not time critical, always use a pessimistic udelay. Not sure what the final suggestion for those was either As for the implementation, I like the suggestion to split outb_b into two calls, one to outb and one to isa_slow_down_io. It makes it very obvious that it is really two function calls, and that it needs locking. For those uses that are not ISA port accesses, isa_slow_down_io should be changed to an appropriate udelay instead. ... or simply deleted. The current outb_p is outb; slow_down_io as a macro so that with this you also get no binary changes, making it rather easy to prove that things do not change timing in cases where you keep the delay. (they're not so much function calls though -- they're inlined). The goal is anyway that a modern machine should
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 1 Jan 2008, H. Peter Anvin wrote: It's specifically a side effect *we don't care about*, except in the by-now-somewhat-exotic case of 386+387 (where we indeed can't use it once user code has touched the FPU -- but we can fall back to 0x80 on those, a very small number of systems.) 486+ doesn't use this interface under Linux, since Linux uses the proper exception path on those processors. If Compaq had wired up the proper signals on the first 386 PC motherboards, we wouldn't have cared about it on the 386 either. It was actually IBM who broke it with the 80286-based PC/AT because of the BIOS compatibility -- the vector #0x10 had already been claimed by the original PC for the video software interrupt call (apparently against Intel's recommendation not to use low 32 interrupt vectors for such purposes), so it could not have been reused as is for FP exception handling without breaking existing software. I suppose a more complicated piece of glue logic could have been used along the lines of what eventually went into the i486, but presumably the relatively low level of integration of the PC/AT made such additional circuits hard to justify even if it indeed was considered. Maciej -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, 2008-01-09 at 16:27 +0100, Rene Herman wrote: On 09-01-08 06:30, Christer Weinigel wrote: I'd not expect very time crtical. The current outb_p use gives a delay somewhere between .5 and 2 microseconds as per earlier survey meaning a udelay(1) or 2 would be enough -- again, at the point that udelay() is sensible. New machines don't use the legacy PIC anymore anyway. The floppy controller code uses outb_p. Even though there might be floppy controllers on modern systems, I'd rather leave the floppy code alone since it's supposed to be very fragile. If you still use floppies you deserve what you get. Floppies forever. In practice, leaving it alone isn't going to matter, but in that same practice changing it to udelay() probably doesn't either. The ones to leave alone are the ones that are clumsy/impossible to test and the ones such as in NIC drivers that were specifically tuned. I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? If simple outb_p() deprecation is considered enough instead, no need to touch anything in drivers/, only changes to outb(); udelay() outside drivers/. I'd let Alan decide here. Agree. Zach -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Maciej W. Rozycki wrote: On Tue, 1 Jan 2008, H. Peter Anvin wrote: It's specifically a side effect *we don't care about*, except in the by-now-somewhat-exotic case of 386+387 (where we indeed can't use it once user code has touched the FPU -- but we can fall back to 0x80 on those, a very small number of systems.) 486+ doesn't use this interface under Linux, since Linux uses the proper exception path on those processors. If Compaq had wired up the proper signals on the first 386 PC motherboards, we wouldn't have cared about it on the 386 either. It was actually IBM who broke it with the 80286-based PC/AT because of the BIOS compatibility -- the vector #0x10 had already been claimed by the original PC for the video software interrupt call (apparently against Intel's recommendation not to use low 32 interrupt vectors for such purposes), so it could not have been reused as is for FP exception handling without breaking existing software. I suppose a more complicated piece of glue logic could have been used along the lines of what eventually went into the i486, but presumably the relatively low level of integration of the PC/AT made such additional circuits hard to justify even if it indeed was considered. Supposedly the reason was that the DOS-less cassette BASIC delivered by Microsoft used all the INT instructions except the reserved ones as a weird bytecode interpreter. Bill Gates was fond of that kind of hacks. -hpa -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Zachary Amsden wrote: I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? Why should the bitsize of the CPU matter for this? It seems one of the less meaningful keys for this. Second, as I have mentioned, I don't believe this is really the case, especially not for the PIT, which is still present -- the PIT *semantics* has explicit timing constraints. Third, you still have ISA devices, they're just called LPC or PC104 devices these days. -hpa -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, Jan 09, 2008 at 10:17:24AM -0800, Zachary Amsden wrote: On Wed, 2008-01-09 at 16:27 +0100, Rene Herman wrote: On 09-01-08 06:30, Christer Weinigel wrote: I'd not expect very time crtical. The current outb_p use gives a delay somewhere between .5 and 2 microseconds as per earlier survey meaning a udelay(1) or 2 would be enough -- again, at the point that udelay() is sensible. New machines don't use the legacy PIC anymore anyway. The floppy controller code uses outb_p. Even though there might be floppy controllers on modern systems, I'd rather leave the floppy code alone since it's supposed to be very fragile. If you still use floppies you deserve what you get. Floppies forever. In practice, leaving it alone isn't going to matter, but in that same practice changing it to udelay() probably doesn't either. The ones to leave alone are the ones that are clumsy/impossible to test and the ones such as in NIC drivers that were specifically tuned. I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? ... I don't think the latter statement was true - AFAIR there are Alphas with ISA slots. Agree. Zach cu Adrian -- Is there not promise of rain? Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. Only a promise, Lao Er said. Pearl S. Buck - Dragon Seed -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Wed, 09 Jan 2008 10:18:11 -0800 H. Peter Anvin [EMAIL PROTECTED] wrote: Zachary Amsden wrote: I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? Why should the bitsize of the CPU matter for this? It seems one of the less meaningful keys for this. Well, anything that runs x86_64 should be a fairly modern system. Second, as I have mentioned, I don't believe this is really the case, especially not for the PIT, which is still present -- the PIT *semantics* has explicit timing constraints. Third, you still have ISA devices, they're just called LPC or PC104 devices these days. Or PCMCIA. I'm still a happy user of a Zyxel ZyAIR 100B, it's one of the most stable cards Wifi I've got running under Linux. :-) /Christer -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Hi, David P. Reed dpreed at reed.com writes: And actually, if I had looked at the /sys/bus/pnp definitions, rather than /proc/ioports, I would have noticed that port 80 was part of a PNP0C02 resource set. That means exactly one thing: ACPI says that port 80 is NOT free to be used, for delays or anything else. I have some computers where port 0x80 is claimed by 8237A DMA controller [1] But in this case it seems a lasy acpi programmer that doesn't want to convert the hole in 0x80-0x8f range... PS : I post from gmane web interface, so I can't keep CC. [1] This happen with a old 7 years old siemens PIII and a new hp core2duo. state = active io 0x0-0xf io 0x80-0x8f io 0xc0-0xdf dma 4 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 2008-01-08 at 21:19 -0800, H. Peter Anvin wrote: Zachary Amsden wrote: BTW, it isn't ever safe to pass port 0x80 through to hardware from a virtual machine; some OSes use port 0x80 as a hardware available scratch register (I believe Darwin/x86 did/does this during boot). That's funny, because there is definitely no guarantee that you get back what you read (well, perhaps there is on Apple.) According to Phoenix Technologies book System BIOS for IBM PCs, Compatibles and EISA Computers, 2nd Edition, the I/O port list gives port 0080h R/W Extra page register (temporary storage) Despite looking, I've never seen it documented anywhere else, but I believe it works on just about every PC platform. Except, apparently, my laptop. Zach -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Zachary Amsden wrote: According to Phoenix Technologies book System BIOS for IBM PCs, Compatibles and EISA Computers, 2nd Edition, the I/O port list gives port 0080h R/W Extra page register (temporary storage) Despite looking, I've never seen it documented anywhere else, but I believe it works on just about every PC platform. Except, apparently, my laptop. The port 80 problem was discovered by me, after months of bisecting the running code around a problem with hanging when using hwclock in 64-bit mode when ACPI is on. So it kills my laptop, too, and many currentlaptop motherboards designed by Quanta for HP and Compaq (dv6000, dv9000, tx1000, apparently) In the last couple of weeks, I was able with luck to discover that the problem is the ENE KB3920 chip, which is the big brother of the KB3700 chip included in the OLPC XO $100 laptop made also by Quanta. I verified this by taking my laptop apart - a fun and risky experience. Didn't break any connectors, but I don't recommend it for those who are not experienced disassembling laptops and cellphones, etc. The KB3920 contains an EC, an SMBus, a KBC, some watchdog timers, and a variety of other functions that keep the laptop going, coordinating the relationships among various peripherals. The firmware is part standard from ENE, part OEM-specific, in this case coded by Quanta or a BIOS subcontractor. You can read the specsheet for the KB3700 online at laptop.org, since the specs of the laptop are open. The 3920's spec is confidential. And the firmware is confidential as well for both the 3700 and 3920. Clues as to what it does can be gleaned by reading the disassembler output of the DSDT code in the particular laptops - though the SMM BIOS probably also talks to it. Modern machines have many subsystems, and the ACPI and SMBIOS coordinate to run them; blade servers also have drawer controllers and backplane management buses. The part that runs Linux is only part of the machine. Your laptop isn't an aberration. It's part of the new generation of evolved machines that take advantage of the capabilities of ACPI and SMBIOS and DMI standards that are becoming core parts of the market. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Christer Weinigel wrote: On Wed, 09 Jan 2008 10:18:11 -0800 H. Peter Anvin [EMAIL PROTECTED] wrote: Zachary Amsden wrote: I'm speaking specifically in terms of 64-bit platforms here. Shouldn't we unconditionally drop outb_p doing extra port I/O on 64-bit architectures? Especially considering they don't even have an ISA bus where the decode timing could even matter? Why should the bitsize of the CPU matter for this? It seems one of the less meaningful keys for this. Well, anything that runs x86_64 should be a fairly modern system. Yes, but you hardly want a situation where the machine works booting a 32-bit kernel and not a 64-bit kernel, or vice versa. Furthermore, it's not so much about modern versus old, it is about picking a certain set of bugs. -hpa -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
David P. Reed wrote: Christer Weinigel wrote: Did I miss anyting? Nothing that seems *crucial* going forward for Linux. The fate of legacy machines is really important to get right. I have a small suggestion in mind that might be helpful in the future: the motherboard resources discovered as PNP0C02 devices in their _CRS settings in ACPI during ACPI PnP startup should be reserved (or checked), and any drivers that still use port 80 implicitly should reserve that port. I agree. In this case the BIOS on these laptops is trying to tell us port 80 is used for our purposes, do not touch it. We should be listening. -- Robert Hancock Saskatoon, SK, Canada To email, remove nospam from [EMAIL PROTECTED] Home Page: http://www.roberthancock.com/ -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 10-01-08 01:37, Robert Hancock wrote: David P. Reed wrote: I have a small suggestion in mind that might be helpful in the future: the motherboard resources discovered as PNP0C02 devices in their _CRS settings in ACPI during ACPI PnP startup should be reserved (or checked), and any drivers that still use port 80 implicitly should reserve that port. I agree. In this case the BIOS on these laptops is trying to tell us port 80 is used for our purposes, do not touch it. We should be listening. Listening is fine but what are you going to do after you have listened? Right, not use port 0x80 but since that's the current idea anyway outside of legacy drivers, you don't actually need to listen. If the quirk-to-0xed or similar was to stay, it's a much better switching point than DMI strings but if not, it's not actually important. Rene. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 08 Jan 2008 18:52:42 -0800 Zachary Amsden <[EMAIL PROTECTED]> wrote: > On Tue, 2008-01-08 at 14:15 -0500, David P. Reed wrote: > > Alan Cox wrote: > > > The natsemi docs here say otherwise. I trust them not you. > > > > > As well you should. I am honestly curious (for my own satisfaction) > > as to what the natsemi docs say the delay code should do (can't > > imagine they say "use io port 80 because it is unused"). I don't > > have any > > What is the outcome of this thread? Are we going to use timing based > port delays, or can we finally drop these things entirely on 64-bit > architectures? > > I a have a doubly vested interest in this, both as the owner of an > affected HP dv9210us laptop and as a maintainer of paravirt code - and > would like 64-bit Linux code to stop using I/O to port 0x80 in both > cases (as I suspect would every other person involved with > virtualization). > > I've tried to follow this thread, but with all the jabs, 1-ups, and > obscure legacy hardware pageantry going on, it isn't clear what we're > really doing. I belive Alan Cox is doing a review of some drivers, to see if they actually need the I/O port delay. A lot of drivers probably use outb_p just because it was copy-pasted from some other driver and it can be removed. Alan's review has also brought to light a lack of locking in some drivers, so I think Alan has been adding proper locking to some of the watchdog drivers. Most old ISA only device drivers can keep using OUT 80h. They are not used on modern machines and it's better to keep them unchanged to avoid unneccesary incompatibilities. As far as I know, the 8253 PIT timer code needs outb_p on some older platform, and this is one of the most troublesome since the same PIT controller (or a register compatible one) has been used since the original IBM PC, and it is frequently executed code. Ingo Molnar has done an alternate implementation of the PIT clock source which uses udelay instead of OUT 80h to delay accesses to the ports. The kernel could make a choice of which variant to use based on the DMI year, if compiling for x86_64, or something similar. Maybe have a command line option too. The keyboard controller on some platform needs the delay, and the same driver is used on both ancient and modern systems, I think it can be changed to udelay since it's not so time critical code. The 8259 interrupt controller on some platform needs the delay, I think it can be changed to udelay since it's only some setup code that uses outb_p. I guess there are time critical accesses to the interrupt controller from assembly code somewhere to acknowledge interrupts, and that code needs a review. The floppy controller code uses outb_p. Even though there might be floppy controllers on modern systems, I'd rather leave the floppy code alone since it's supposed to be very fragile. If you still use floppies you deserve what you get. Some specific drivers, such as drivers for 8390 or 8390 clone based network cards are also a bit troublesome, they do need outb_p (and the delay for the original 8390 chip is specified in bus cycles), and there can be a big performance loss if pessimistic udelays are used for the delay. There are still a bunch of PCMCIA cards based on that chip which means that those cards can be used with modern machines. There are also PCI and memory mapped variants of the 8390, some of them new designs which are only register compatible, some other designs are using a real 8390 with a FPGA used as glue logic. I think Alan suggested compiling two versions of that driver, one with OUT 80h, and one with udelay. Old machines can choose the old driver, and new machines can use the new one. Other drivers can probably do the same thing, or if not time critical, always use a pessimistic udelay. As for the implementation, I like the suggestion to split outb_b into two calls, one to outb and one to isa_slow_down_io. It makes it very obvious that it is really two function calls, and that it needs locking. For those uses that are not ISA port accesses, isa_slow_down_io should be changed to an appropriate udelay instead. The goal is anyway that a modern machine should not do OUT 80h, and old machines keep doing it since it has been working well for some 15-odd years, both in DOS device drivers and on Linux. Using an alternate port may be a workaround, but it's probaby not a good idea since alternate ports have received less testing and there's bound to be some platform out there that has problems with any alternate port we might choose. Allowing an alternate port will also add code bloat (OUT 80h, AL becomes MOV DX, alternate_port; OUT DX, AL) for a dubious gain. Did I miss anyting? /Christer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Zachary Amsden wrote: BTW, it isn't ever safe to pass port 0x80 through to hardware from a virtual machine; some OSes use port 0x80 as a hardware available scratch register (I believe Darwin/x86 did/does this during boot). That's funny, because there is definitely no guarantee that you get back what you read (well, perhaps there is on Apple.) -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 2008-01-08 at 14:15 -0500, David P. Reed wrote: > Alan Cox wrote: > > The natsemi docs here say otherwise. I trust them not you. > > > As well you should. I am honestly curious (for my own satisfaction) as > to what the natsemi docs say the delay code should do (can't imagine > they say "use io port 80 because it is unused"). I don't have any What is the outcome of this thread? Are we going to use timing based port delays, or can we finally drop these things entirely on 64-bit architectures? I a have a doubly vested interest in this, both as the owner of an affected HP dv9210us laptop and as a maintainer of paravirt code - and would like 64-bit Linux code to stop using I/O to port 0x80 in both cases (as I suspect would every other person involved with virtualization). BTW, it isn't ever safe to pass port 0x80 through to hardware from a virtual machine; some OSes use port 0x80 as a hardware available scratch register (I believe Darwin/x86 did/does this during boot). This means simultaneous execution of two virtual machines can interleave port 0x80 values or share data with a hardware provided covert channel. This means KVM should be trapping port 0x80 access, which is really expensive, or alternatively, Linux should not be using port 0x80 for timing bus access on modern (64-bit) hardware. I've tried to follow this thread, but with all the jabs, 1-ups, and obscure legacy hardware pageantry going on, it isn't clear what we're really doing. Thanks, Zach -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Christer Weinigel wrote: Argument by personal authority. Thats good. There is no other kind of argument. Are you claiming supernatural authority drives your typing fingers, or is your argument based on what you think you know? I have piles of code that I wrote, spec sheets (now that I'm back in my home office), code that others wrote at the time, and documentation from vendors that come from my personal experiences. That doesn't mean I'm always right - always happy to learn something new. Just don't condescend to a 55 year old who has been writing operating systems, compilers, and designing hardware for almost 40 years professionally (yes, I got my first job at 16 writing FORTRAN code to simulate hydrodynamic systems). I guess that's why you don't seem to understand the difference between reading the serial port status register and not being allowed to access a register at all due to such this as the 4 cycle delay you quoted yourself from the 8390 data sheet, If you read what I said carefully, I said that the 8390 was a very special case. The "chip select" problem it experienced was pretty much unique among boards of the time. Those of us who looked at its design and had any experience designing hardware for buses like the unibus or even the buses on PDP-8's and DG machines thought it had to be a joke. Of course it saved money per board, so it beat the 3Com boards on price - and you could program it after a fashion. So it involved "cheaping out". The normal timing problem was that an out or in operation to a board or chip required some time to elapse before the chip performed the side effects internally so that the next operation to it would have an effect. This is exactly the reason why most chips and boards are designed to either have a polling of a flag indicate operation completion. The serial "buffer empty" flag is the simplest possible explanatory example of such handshaking that came to mind (writing a character to a serial output device twice often leads to surprises, unless you wait for the previous character to clock out). See my comment on RTC below, for a more complex to explain example. and similar issues with the I8253 that I quoted from its data sheet a few posts ago. The 8253 was a motherboard chip. I am not sure it had any timing problems with its electrical signalling. I just don't remember. The spec sheet doesn't say it's internal state can get scrambled. I was thinking of another timer, the RTC which is usually a part of the Super I/O. The RTC has very well documented timing requirements. But none of the spec sheets, nor my experience with it, mention electrical issues that prevented back-to-back port operations. The documented timing requirements have to do with the state during the time it ticks over internally once per second. But it is carefully designed to have a flag that is "on" during 244 microseconds prior to and covering the time it is unsafe to read the registers. That design is special because it is designed to operate when the machine is powered off, so it has two internal clock domains, one of which is used in "low power" mode and is very slow to minimize power. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 08 Jan 2008 15:28:03 -0500 "David P. Reed" <[EMAIL PROTECTED]> wrote: > Register compatible. Not the same chips or even the same masks or > timing requirements. No, but somehow people keep making similar mistakes. The DEC HiNote needed outb_p to function correctly? That was definitely a much more modern design than the original PC and most probably did not use any discrete Intel chips, but the same timing problems were there. I belive that problem had to do with the keyboard controller though. > > The discrete Intel > > chips or clones got aggregated into Super I/O chips, and the Super > > I/O chips were put on a LPC bus (an ISA bus with another name) or > > integrated into the southbrige. > Don't try to teach your grandmother to suck eggs: I've been > programming PC compatibles since probably before you were able to do > long division - including writing code on the first prototype IBM > PCs, the first pre-manufacturing PC-ATs, and zillions of clones. > (and I was also involved in designing hardware including the > so-called "Lotus Intel" expanded memory cards and the original PC > cards) Argument by personal authority. Thats good. I guess that's why you don't seem to understand the difference between reading the serial port status register and not being allowed to access a register at all due to such this as the 4 cycle delay you quoted yourself from the 8390 data sheet, and similar issues with the I8253 that I quoted from its data sheet a few posts ago. > The 8259 PIC is an *interrupt controller*. It was NEVER > present in a Super I/O chip, or an LPC chip. Its functionality was > absorbed into the chipsets that control interrupt mapping, like the > PIIX and the nForce. Yup, sorry about that, it got integrated into some other chip instead. I was thinking of another timer, the RTC which is usually a part of the Super I/O. And which is yet another troublesome area since apparently a lot of chipsets have problems with it. But the sequence is the same, discrete chips get aggregated into larger chips. Sometimes the sometimes old macrocells are reused, sometimes they are redesigned from scratch (and new bugs are introduced). > > And the "if it ain't broken, don't fix > > it" mantra probably means that some modern chipsets are still using > > exactly the same internal design as the 25 year old chips and will > > still be subject to some of those ancient limitations. > > > Oh, come on. Give the VLSI designers some credit for brains. The > CAD tools used to design the 8259 and 8253 were so primitive you > couldn't even get a chip manufactured with designs from that era > today. When people design chips today they do it with simulators > that can't even work, and testers that run from test suites that were > not available at the time. And they still keep making the same mistakes... Registers that require wait states before being read again, register that assume that there are going to be some spare cycles between each access so that some internal logic has time to update, registers that would have needed a one byte FIFO to avoid DMA overruns (I'd almost forgotten about that specific bug on SPI controller of the Samsung 2410, but it bit me last week and I only managed to chase it down properly yesterday), and so on. I'm quite impressed with what some VLSI designers manage to do. I just saw a company roll out a completely new ARM9 design with lots of fun stuff and as far as I know they only made one single mistake on that chip. On the other hand, on other designs you can see how the same old macrocell has been reused long past the "best before" date, because some bugs crop up over and over again. /Christer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Christer Weinigel wrote: There is no need to use io writes to supposedly/theoretically "unused ports" to make drivers work on any bus. ISA included! You can, for example, wait for an ISA bus serial adapter to put out its next character by looping reading the port that has the output buffer full flag in a tight loop, with no delay code at all. And if you need to time things, just call a timing loop subroutine that you calibrate at boot time. Now you're totally confusing things. You're talking about looking at bits in a register to see if a transmit register is empty. That's easy. The delays needed for the Intel M8259 and M8253 say that you're not even allowed to access the registers _at_ _all_ for some time after a register access. If you do a write to a register immediately followed by any access, including a read of the status register, you can corrupt the state of the chip. Not true. Even on the original IBM 5150 PC, the 8259 on the motherboard accepted back to back OUT and IN instructions, and it would NOT trash the chip state. You can read the original IBM BIOS code if you like. I don't remember about the 8253's timing. I doubt the chip's state would be corrupted in any way. The data and address lines were the same data and address lines that the microprocessor used to access memory - it didn't "hold" the lines stable any longer than the OUT instruction. And the Intel chips are not the only ones with that kind of brain damage. But what makes the 8259 and 8253 a big problem is that every modern PC has a descendant of those chips in them. Register compatible. Not the same chips or even the same masks or timing requirements. The discrete Intel chips or clones got aggregated into Super I/O chips, and the Super I/O chips were put on a LPC bus (an ISA bus with another name) or integrated into the southbrige. Don't try to teach your grandmother to suck eggs: I've been programming PC compatibles since probably before you were able to do long division - including writing code on the first prototype IBM PCs, the first pre-manufacturing PC-ATs, and zillions of clones. (and I was also involved in designing hardware including the so-called "Lotus Intel" expanded memory cards and the original PC cards) The 8259 PIC is an *interrupt controller*. It was NEVER present in a Super I/O chip, or an LPC chip. Its functionality was absorbed into the chipsets that control interrupt mapping, like the PIIX and the nForce. And the "if it ain't broken, don't fix it" mantra probably means that some modern chipsets are still using exactly the same internal design as the 25 year old chips and will still be subject to some of those ancient limitations. Oh, come on. Give the VLSI designers some credit for brains. The CAD tools used to design the 8259 and 8253 were so primitive you couldn't even get a chip manufactured with designs from that era today. When people design chips today they do it with simulators that can't even work, and testers that run from test suites that were not available at the time. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan - I dug up a DP83901A SNIC datasheet in a quick Google search, while that wasn't the only such chip, it was one of them. I can forward the PDF (the www.alldatasheet.com site dynamically creates the download URL), if anyone wants it. The relevant passage says, in regard to delaying between checking the CRDA addresses to see if a dummy "remote read" has been executed., and in regard perhaps to other card IO register loops: TIME BETWEEN CHIP SELECTS The SNIC requires that successive chip selects be no closer than 4 bus clocks (BSCK) together. If the condition is violat- ed the SNIC may glitch ACK. CPUs that operate from pipe- lined instructions (i e 386) or have a cache (i e 486) can execute consecutive I O cycles very quickly The solution is to delay the execution of consecutive I O cycles by either breaking the pipeline or forcing the CPU to access outside its cache. The NE2000 as I recall had no special logic on the board to protect the chip from successive chip selects that were too close - which is the reason for the problem. Clearly an out to port 80 takes more than 4 ISA bus clocks, so that works if the NE2000 is on the ISA bus, On the other hand, there are other ways to delay more than 4 ISA bus clocks. And as you say, one needs a delay for this chip that relates to the chip's card's bus's clock speed, not absolute time. Alan Cox wrote: As well you should. I am honestly curious (for my own satisfaction) as to what the natsemi docs say the delay code should do (can't imagine they say "use io port 80 because it is unused"). I don't have any They say you must allow 4 bus clocks for the address decode. They don't deal with the ISA side as the chip itself has no ISA glue. copies anymore. But mere curiosity on my part is not worth spending a lot of time on - I know you are super busy. If there's a copy online at a URL ... Not that I know of. There may be. A good general source of info is Russ Nelson's old DOS packet driver collection. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 08 Jan 2008 13:44:54 -0500 "David P. Reed" <[EMAIL PROTECTED]> wrote: > Ondrej Zary wrote: > > On Tuesday 08 January 2008 18:24:02 David P. Reed wrote: > > > >> Windows these days does delays with timing loops or the > >> scheduler. It doesn't use a "port". Also, Windows XP only > >> supports machines that tend not to have timing problems that use > >> delays. Instead, if a device takes a while to respond, it has a > >> "busy bit" in some port or memory slot that can be tested. > >> > There is no need to use io writes to supposedly/theoretically "unused > ports" to make drivers work on any bus. > ISA included! You can, for example, wait for an ISA bus serial > adapter to put out its next character by looping reading the port > that has the output buffer full flag in a tight loop, with no delay > code at all. And if you need to time things, just call a timing loop > subroutine that you calibrate at boot time. Now you're totally confusing things. You're talking about looking at bits in a register to see if a transmit register is empty. That's easy. The delays needed for the Intel M8259 and M8253 say that you're not even allowed to access the registers _at_ _all_ for some time after a register access. If you do a write to a register immediately followed by any access, including a read of the status register, you can corrupt the state of the chip. And the Intel chips are not the only ones with that kind of brain damage. But what makes the 8259 and 8253 a big problem is that every modern PC has a descendant of those chips in them. The discrete Intel chips or clones got aggregated into Super I/O chips, and the Super I/O chips were put on a LPC bus (an ISA bus with another name) or integrated into the southbrige. And the "if it ain't broken, don't fix it" mantra probably means that some modern chipsets are still using exactly the same internal design as the 25 year old chips and will still be subject to some of those ancient limitations. /Christer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> As well you should. I am honestly curious (for my own satisfaction) as > to what the natsemi docs say the delay code should do (can't imagine > they say "use io port 80 because it is unused"). I don't have any They say you must allow 4 bus clocks for the address decode. They don't deal with the ISA side as the chip itself has no ISA glue. > copies anymore. But mere curiosity on my part is not worth spending a > lot of time on - I know you are super busy. If there's a copy online > at a URL ... Not that I know of. There may be. A good general source of info is Russ Nelson's old DOS packet driver collection. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Alan Cox wrote: The natsemi docs here say otherwise. I trust them not you. As well you should. I am honestly curious (for my own satisfaction) as to what the natsemi docs say the delay code should do (can't imagine they say "use io port 80 because it is unused"). I don't have any copies anymore. But mere curiosity on my part is not worth spending a lot of time on - I know you are super busy. If there's a copy online at a URL ... The problem is that certain people, unfortunately those who know nothing about ISA related bus systems, keep trying to confuse ISA delay logic with core chip logic and end up trying to solve both a problem and a non-problem in one, creating a nasty mess in the process. I agree that the problems of chip logic and ISA delay are all tangled up, probably more than need be. I hope that the solution turns out to simplify matters, and hopefully to document the intention of the resulting code sections a bit more clearly for the future. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tuesday 08 January 2008 19:51:41 Bodo Eggert wrote: > On Tue, 8 Jan 2008, Ondrej Zary wrote: > > On Tuesday 08 January 2008 18:24:02 David P. Reed wrote: > > > Windows these days does delays with timing loops or the scheduler. It > > > doesn't use a "port". Also, Windows XP only supports machines that > > > tend not to have timing problems that use delays. Instead, if a device > > > takes a while to respond, it has a "busy bit" in some port or memory > > > slot that can be tested. > > > > Windows XP can run on a machine with ISA slot(s) and has built-in drivers > > for some plug ISA cards - e.g. the famous 3Com EtherLink III. I > > think that there's a driver for NE2000-compatible cards too and it > > probably works. > > The NE2K-driver went missing in W2K. BTDT. Haven't tried personally but it seems to work accroding to this http://www.windowsnetworking.com/articles_tutorials/wxpne2k.html - and it can be made to work even with non-PnP cards. -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 8 Jan 2008, Ondrej Zary wrote: > On Tuesday 08 January 2008 18:24:02 David P. Reed wrote: > > Windows these days does delays with timing loops or the scheduler. It > > doesn't use a "port". Also, Windows XP only supports machines that tend > > not to have timing problems that use delays. Instead, if a device takes > > a while to respond, it has a "busy bit" in some port or memory slot that > > can be tested. > > Windows XP can run on a machine with ISA slot(s) and has built-in drivers for > some plug ISA cards - e.g. the famous 3Com EtherLink III. I think that > there's a driver for NE2000-compatible cards too and it probably works. The NE2K-driver went missing in W2K. BTDT. -- Anyone can speak Troll. All you have to do is point and grunt. -- Fred Weasley -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> There is no need to use io writes to supposedly/theoretically "unused > ports" to make drivers work on any bus. The natsemi docs here say otherwise. I trust them not you. > don't remember writing a driver for the 3com devices - probably didn't, > because 3Com's cards were expensive at the time. 3C503 needs delays for some setups according to the docs. I can't tell you how the 3COM drivers did it as that was a different bit of 3com to the bit I worked for. From the rest of 3Com I saw probably utterly vilely ;) Later 3Com stuff was either sane (3c509 etc) or used whacko intel chips (3c507/27) which had their own special breed of insanity to replace address setup delay bugs. > In any case, Linux *did* adopt this port 80 strategy - I'm sure all > concerned thought it was frightfully clever at the time. Linus > expressed his skepticism in the comments in io.h. The problem is to > safely move away from it toward a proper strategy No. The problem is that certain people, unfortunately those who know nothing about ISA related bus systems, keep trying to confuse ISA delay logic with core chip logic and end up trying to solve both a problem and a non-problem in one, creating a nasty mess in the process. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Ondrej Zary wrote: On Tuesday 08 January 2008 18:24:02 David P. Reed wrote: Windows these days does delays with timing loops or the scheduler. It doesn't use a "port". Also, Windows XP only supports machines that tend not to have timing problems that use delays. Instead, if a device takes a while to respond, it has a "busy bit" in some port or memory slot that can be tested. Windows XP can run on a machine with ISA slot(s) and has built-in drivers for some plug ISA cards - e.g. the famous 3Com EtherLink III. I think that there's a driver for NE2000-compatible cards too and it probably works. There is no need to use io writes to supposedly/theoretically "unused ports" to make drivers work on any bus. ISA included! You can, for example, wait for an ISA bus serial adapter to put out its next character by looping reading the port that has the output buffer full flag in a tight loop, with no delay code at all. And if you need to time things, just call a timing loop subroutine that you calibrate at boot time. I wrote DOS drivers for NE2000's on the ISA bus when they were brand new designs from Novell without such kludges as writes to I/O port 80. I don't remember writing a driver for the 3com devices - probably didn't, because 3Com's cards were expensive at the time. In any case, Linux *did* adopt this port 80 strategy - I'm sure all concerned thought it was frightfully clever at the time. Linus expressed his skepticism in the comments in io.h. The problem is to safely move away from it toward a proper strategy that doesn't depend on "bus aborts" which would trigger machine checks if they were properly enabled. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tuesday 08 January 2008 18:24:02 David P. Reed wrote: > Windows these days does delays with timing loops or the scheduler. It > doesn't use a "port". Also, Windows XP only supports machines that tend > not to have timing problems that use delays. Instead, if a device takes > a while to respond, it has a "busy bit" in some port or memory slot that > can be tested. Windows XP can run on a machine with ISA slot(s) and has built-in drivers for some plug ISA cards - e.g. the famous 3Com EtherLink III. I think that there's a driver for NE2000-compatible cards too and it probably works. > Almost all of the issues in Linux where _p operations are used are (or > should be) historical - IMO. > > Ondrej Zary wrote: > > On Tuesday 08 January 2008 02:38:15 David P. Reed wrote: > >> H. Peter Anvin wrote: > >>> And shoot the designer of this particular microcontroller firmware. > >> > >> Well, some days I want to shoot the "designer" of the entire Wintel > >> architecture... it's not exactly "designed" by anybody of course, and > >> today it's created largely by a collection of Taiwanese and Chinese ODM > >> firms, coupled with Microsoft WinHEC and Intel folks. At least they > >> follow the rules and their ACPI and BIOS code say that they are using > >> port 80 very clearly if you use PnP and ACPI properly. And in the old > >> days, you were "supposed" to use the system BIOS to talk to things like > >> the PIT that had timing issues, not write your own code. > > > > Does anyone know what port does Windows use? I'm pretty sure that it > > isn't 80h as I run Windows 98 often with port 80h debug card inserted. > > The last POST code set by BIOS usually remains on the display and only > > changes when BIOS does something like suspend/resume. IIRC, there was a > > program that was able to display temperature from onboard sensors on the > > port 80h display that's integrated on some mainboards. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
Windows these days does delays with timing loops or the scheduler. It doesn't use a "port". Also, Windows XP only supports machines that tend not to have timing problems that use delays. Instead, if a device takes a while to respond, it has a "busy bit" in some port or memory slot that can be tested. Almost all of the issues in Linux where _p operations are used are (or should be) historical - IMO. Ondrej Zary wrote: On Tuesday 08 January 2008 02:38:15 David P. Reed wrote: H. Peter Anvin wrote: And shoot the designer of this particular microcontroller firmware. Well, some days I want to shoot the "designer" of the entire Wintel architecture... it's not exactly "designed" by anybody of course, and today it's created largely by a collection of Taiwanese and Chinese ODM firms, coupled with Microsoft WinHEC and Intel folks. At least they follow the rules and their ACPI and BIOS code say that they are using port 80 very clearly if you use PnP and ACPI properly. And in the old days, you were "supposed" to use the system BIOS to talk to things like the PIT that had timing issues, not write your own code. Does anyone know what port does Windows use? I'm pretty sure that it isn't 80h as I run Windows 98 often with port 80h debug card inserted. The last POST code set by BIOS usually remains on the display and only changes when BIOS does something like suspend/resume. IIRC, there was a program that was able to display temperature from onboard sensors on the port 80h display that's integrated on some mainboards. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tuesday 08 January 2008 02:38:15 David P. Reed wrote: > H. Peter Anvin wrote: > > And shoot the designer of this particular microcontroller firmware. > > Well, some days I want to shoot the "designer" of the entire Wintel > architecture... it's not exactly "designed" by anybody of course, and > today it's created largely by a collection of Taiwanese and Chinese ODM > firms, coupled with Microsoft WinHEC and Intel folks. At least they > follow the rules and their ACPI and BIOS code say that they are using > port 80 very clearly if you use PnP and ACPI properly. And in the old > days, you were "supposed" to use the system BIOS to talk to things like > the PIT that had timing issues, not write your own code. Does anyone know what port does Windows use? I'm pretty sure that it isn't 80h as I run Windows 98 often with port 80h debug card inserted. The last POST code set by BIOS usually remains on the display and only changes when BIOS does something like suspend/resume. IIRC, there was a program that was able to display temperature from onboard sensors on the port 80h display that's integrated on some mainboards. -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> As long as there is no port 80 card or a similar device using it. If > there is a port 80 card, ISA acess needing the delay does break Such cards are very unusual on ISA machines and it hasn't been a problem in fifteen years. All the alternatives are vastly higher risk -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> The last time I heard of a 12 MHz bus in a PC system was in the days of > the PC-AT, when some clone makers sped up their buses (pre PCI!!!) in an > attempt to allow adapter card *memory* to run at the 12 MHz speed. It wasn't about clone makers speeding up their busses. The ISA bus originally ran at the CPU clock - 4.77/8/6/10 .. etc. Quite a few board makers assumed 8MHz and while faster isn't a big problem at 8bit trying to do the 8/16 bit decode with logic chips at 8MHz is quite tight and above that generally broke. 8bit tends to work fine because you've got a lot more timing headroom. > I can't believe that we are not supporting today's machines correctly > because we are still trying to be compatible with a few (at most a > hundre thousand were manufactured! Much less still functioning or > running Linux) machines. It is about supporting this properly. Properly for ISA devices means using I/O delays. Properly for chipset devices is probably using udelay. > Now I understand that PC/104 machines and other things are very non PC > compatible, but are x86 processor architectures. Do they even run x86 > under 2.6.24? Linux runs on x86, it isn't limited to PC type architectures at all. We don't need a BIOS, we don't need legacy compatible I/O devices. > for "relics" and develop a merged architecture called "modern machines" > to include only those PCs that have been made to work since, say, the > release of (cough) WIndows 2000? No point. We've got the 64bit kernel for that. That is a much saner boundary to throw out all the nutty stuff. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
> OTOH, the DOS drivers I heared about use delays and would break on > underclocked ISA busses if the n * ISA_HZ delay was needed. Maybe > somebody having a configurable ISA bus speed and some problematic > chips can test it ... I've been looking at DOS reference drivers - they almost all use I/O port based delays. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On 08-01-08 13:51, Bodo Eggert wrote: On Tue, 8 Jan 2008, Rene Herman wrote: Is this only about the ones then left for things like legacy PIC and PIT? Does anyone care about just sticking in a udelay(2) (or 1) there as a replacement and call it a day? PIT is problematic because the PIT may be necessary for udelay setup. Yes, can initialise loops_per_jiffy conservatively. Just didn't quite get why you guys are talking about an ISA bus speed parameter. If the ISA bus is below 8 MHz, we might need a longer delay. If we default to the longer delay, the delay will be too long for more than 99,99 % of all systems, not counting i586+. Especially if the driver is fine-tuned to give maximum throughput, this may be bad. Yes, and I repeat -- old legacy ISA drivers can stay as they are. They've been doing what they've been doing for 15 years and given that the systems that break don't use them there is no practical upside to changing them and a big downside particularly with respect to difficulty of testing. A somewhat overly long delay shouldn't be particularly problematic for the few remaining legacy hardware users _outside_ drivers/ Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Mon, 7 Jan 2008, Alan Cox wrote: > > But overclocking is not the problem for udelay, it would err to the safe > > side. The problem would be a BUS having < 8 MHz, and since the days of > > 80286, they are hard to find. IMO having an option to set the bus speed > > for those systems should be enough. > > If you get it wrong you risk data corruption. Not good, not clever, not > appropriate. Basically the use of port 0x80 is the right thing to do for > ISA devices and as 15 odd years of use has shown works reliably and > solidly for ISA systems. As long as there is no port 80 card or a similar device using it. If there is a port 80 card, ISA acess needing the delay does break, cause the data corruption you fear and does cause this thread to be started. Pest, Cholera ... OTOH, maybe the 6-MHz-delay is the same as the 8-MHz-delay, and the kernel parameter is not needed. -- Fun things to slip into your budget A Romulan Cloaking device: The PHB won't know what it is but will be to chicken to ask -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
The last time I heard of a 12 MHz bus in a PC system was in the days of the PC-AT, when some clone makers sped up their buses (pre PCI!!!) in an attempt to allow adapter card *memory* to run at the 12 MHz speed. This caused so many industry-wide problems with adapter cards that couldn't be installed in certain machines and still run reliably that the industry learned a lesson. That doesn't mean that LPCs don't run at 12 MHz, but if they do, they don't have old 8 bit punky cards plugged into them for lots of practical reasons. (I have whole drawers full of such old cards, trying to figure out an environmentally responsible way to get rid of them - even third world countries would be fools to make machiens with them). I can't believe that we are not supporting today's machines correctly because we are still trying to be compatible with a few (at most a hundre thousand were manufactured! Much less still functioning or running Linux) machines. Now I understand that PC/104 machines and other things are very non PC compatible, but are x86 processor architectures. Do they even run x86 under 2.6.24? Perhaps the rational solution here is to declare x86 the architecture for "relics" and develop a merged architecture called "modern machines" to include only those PCs that have been made to work since, say, the release of (cough) WIndows 2000? Bodo Eggert wrote: On Tue, 8 Jan 2008, Rene Herman wrote: On 08-01-08 00:24, H. Peter Anvin wrote: Rene Herman wrote: Is this only about the ones then left for things like legacy PIC and PIT? Does anyone care about just sticking in a udelay(2) (or 1) there as a replacement and call it a day? PIT is problematic because the PIT may be necessary for udelay setup. Yes, can initialise loops_per_jiffy conservatively. Just didn't quite get why you guys are talking about an ISA bus speed parameter. If the ISA bus is below 8 MHz, we might need a longer delay. If we default to the longer delay, the delay will be too long for more than 99,99 % of all systems, not counting i586+. Especially if the driver is fine-tuned to give maximum throughput, this may be bad. OTOH, the DOS drivers I heared about use delays and would break on underclocked ISA busses if the n * ISA_HZ delay was needed. Maybe somebody having a configurable ISA bus speed and some problematic chips can test it ... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 8 Jan 2008, Rene Herman wrote: > On 08-01-08 00:24, H. Peter Anvin wrote: > > Rene Herman wrote: > > > Is this only about the ones then left for things like legacy PIC and PIT? > > > Does anyone care about just sticking in a udelay(2) (or 1) there as a > > > replacement and call it a day? > > > > > > > PIT is problematic because the PIT may be necessary for udelay setup. > > Yes, can initialise loops_per_jiffy conservatively. Just didn't quite get why > you guys are talking about an ISA bus speed parameter. If the ISA bus is below 8 MHz, we might need a longer delay. If we default to the longer delay, the delay will be too long for more than 99,99 % of all systems, not counting i586+. Especially if the driver is fine-tuned to give maximum throughput, this may be bad. OTOH, the DOS drivers I heared about use delays and would break on underclocked ISA busses if the n * ISA_HZ delay was needed. Maybe somebody having a configurable ISA bus speed and some problematic chips can test it ... -- Fun things to slip into your budget "I [Meow Cat] sliped in 'Legal fees for firing Jim (Jim's my [his] boss).' Jim approved the budget and was fired when upper management saw the budget." -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
On Tue, 8 Jan 2008, Rene Herman wrote: On 08-01-08 00:24, H. Peter Anvin wrote: Rene Herman wrote: Is this only about the ones then left for things like legacy PIC and PIT? Does anyone care about just sticking in a udelay(2) (or 1) there as a replacement and call it a day? PIT is problematic because the PIT may be necessary for udelay setup. Yes, can initialise loops_per_jiffy conservatively. Just didn't quite get why you guys are talking about an ISA bus speed parameter. If the ISA bus is below 8 MHz, we might need a longer delay. If we default to the longer delay, the delay will be too long for more than 99,99 % of all systems, not counting i586+. Especially if the driver is fine-tuned to give maximum throughput, this may be bad. OTOH, the DOS drivers I heared about use delays and would break on underclocked ISA busses if the n * ISA_HZ delay was needed. Maybe somebody having a configurable ISA bus speed and some problematic chips can test it ... -- Fun things to slip into your budget I [Meow Cat] sliped in 'Legal fees for firing Jim (Jim's my [his] boss).' Jim approved the budget and was fired when upper management saw the budget. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
