Re: [coreboot] disabling bios usb stack
ron minnich [mailto:rminn...@gmail.com] wrote: ]Thanks scott! ] ]So, what does an OS do to disable USB in the operating system? We have ]seen Linux do it, we're not quite sure just what ]place it gets done. ] ]ron If I understand your question, I am not sure I know the answer. If you boot linux with grub option 'nousb', or reboot Windows after disabling usb controllers from device manager, what happens? I assume the operating system just ignores USB controllers. It seems unlikely that the OS would take some action to ensure that they are properly disabled. Does UEFI disable USB controllers before handoff to the OS loader? I do not know. Having the OS not load USB drivers should eliminate USB related interrupts, but I know EHCI can generate memory accesses even when idle. Thanks, Scott -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
The guys found it, bit in southbridge to enable SMI interrupts, they turned it off and are now seeing a 40 hz. interrupt. It never ends. -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
This is really interesting information, thanks. This embedded USB stack problem actually impacts HPC applications. This type of periodic interference can cause big troubles when you have lots of nodes. Look for the case of the missing supercomputer performance for a classic paper. In that case, a 1/30 hz (i.e. lpd dropping out of select every 30 seconds on 2048 nodes) was worth a couple tens of millions of dollars of performance. I'm amazed that the embedded USB stack problems are WORSE, not better, than they were a few years back. The x86 world just keeps getting more backwards. I'm sorry to see the ARM V8 world trying to emulate it. ron On Tue, Aug 26, 2014 at 3:14 PM, Антон Кочков anton.koch...@gmail.com wrote: Hello, Just checked some binaries - PEI USB driver is loading anyway, no checking for any setup option, so I guess it will be very hard even with the unpacking UEFI image and removing these drivers. Also in most UEFI systems big part of USB driver working in SMM mode, so it will be hard to patch this code on the fly. Best regards, Anton Kochkov. On Wed, Aug 27, 2014 at 1:23 AM, Carl-Daniel Hailfinger c-d.hailfinger.devel.2...@gmx.net wrote: Hi Ron, Am 26.08.2014 00:22 schrieb ron minnich: disabling the usb stack is the goal in this case. AFAIK it's called USB keyboard support, USB legacy support or something similar in most BIOSes. This internally maps a USB keyboard to a virtual PS/2 keyboard and sometimes has quite a few issues. If that's what your friend meant, disabling it should be straightforward in the BIOS menu. However, if your friend is a victim of EFI, I fear he is beyond help except for trying coreboot. Regards, Carl-Daniel -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
ron minnich [mailto:rminn...@gmail.com] wrote: ]This is really interesting information, thanks. ] ]This embedded USB stack problem actually impacts HPC applications. ]This type of periodic interference can cause big troubles when you ]have lots of nodes. ] ]Look for the case of the missing supercomputer performance for a ]classic paper. In that case, a 1/30 hz (i.e. lpd dropping out of ]select every 30 seconds on 2048 nodes) was worth a couple tens of ]millions of dollars of performance. ] ]I'm amazed that the embedded USB stack problems are WORSE, not better, ]than they were a few years back. The x86 world just keeps getting more ]backwards. I'm sorry to see the ARM V8 world trying to emulate it. ] ]ron I have seen concern about BIOS SMI overhead from server customers running certain applications. These customers do not want avoidable interruptions of even a few uS. Some server BIOS enable a periodic SMI for various server management uses. This never ending periodic SMI is not wanted by these customers. But I thought all USB related SMI activity ends after a legacy BIOS hands control to an operating system that supports USB. For pure UEFI, I don't believe the USB uses SMI at all. So it would seem like disabling USB in the operating system would be just as good as doing it in BIOS. If an OS that predates USB is used, SMI will continue in order to support legacy 60/64 emulation. In this case, the easiest solution might be to set the global SMI mask in the south bridge, assuming this is the only source of SMI. Thanks, Scott On Tue, Aug 26, 2014 at 3:14 PM, Антон Кочков anton.koch...@gmail.com wrote: Hello, Just checked some binaries - PEI USB driver is loading anyway, no checking for any setup option, so I guess it will be very hard even with the unpacking UEFI image and removing these drivers. Also in most UEFI systems big part of USB driver working in SMM mode, so it will be hard to patch this code on the fly. Best regards, Anton Kochkov. On Wed, Aug 27, 2014 at 1:23 AM, Carl-Daniel Hailfinger c-d.hailfinger.devel.2...@gmx.net wrote: Hi Ron, Am 26.08.2014 00:22 schrieb ron minnich: disabling the usb stack is the goal in this case. AFAIK it's called USB keyboard support, USB legacy support or something similar in most BIOSes. This internally maps a USB keyboard to a virtual PS/2 keyboard and sometimes has quite a few issues. If that's what your friend meant, disabling it should be straightforward in the BIOS menu. However, if your friend is a victim of EFI, I fear he is beyond help except for trying coreboot. Regards, Carl-Daniel -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
Thanks scott! So, what does an OS do to disable USB in the operating system? We have seen Linux do it, we're not quite sure just what place it gets done. ron -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
Hi Ron, Am 26.08.2014 00:22 schrieb ron minnich: disabling the usb stack is the goal in this case. AFAIK it's called USB keyboard support, USB legacy support or something similar in most BIOSes. This internally maps a USB keyboard to a virtual PS/2 keyboard and sometimes has quite a few issues. If that's what your friend meant, disabling it should be straightforward in the BIOS menu. However, if your friend is a victim of EFI, I fear he is beyond help except for trying coreboot. Regards, Carl-Daniel -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
Hello, Just checked some binaries - PEI USB driver is loading anyway, no checking for any setup option, so I guess it will be very hard even with the unpacking UEFI image and removing these drivers. Also in most UEFI systems big part of USB driver working in SMM mode, so it will be hard to patch this code on the fly. Best regards, Anton Kochkov. On Wed, Aug 27, 2014 at 1:23 AM, Carl-Daniel Hailfinger c-d.hailfinger.devel.2...@gmx.net wrote: Hi Ron, Am 26.08.2014 00:22 schrieb ron minnich: disabling the usb stack is the goal in this case. AFAIK it's called USB keyboard support, USB legacy support or something similar in most BIOSes. This internally maps a USB keyboard to a virtual PS/2 keyboard and sometimes has quite a few issues. If that's what your friend meant, disabling it should be straightforward in the BIOS menu. However, if your friend is a victim of EFI, I fear he is beyond help except for trying coreboot. Regards, Carl-Daniel -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
[coreboot] disabling bios usb stack
A friend asks me how to disable the usb stack in his bios. I have no clue, anyone? ron -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
On 25.08.2014 23:28, ron minnich wrote: A friend asks me how to disable the usb stack in his bios. I have no clue, anyone? Doesn't sound like end goal. But I'd go through setup menu to see if something fits his *end* goal (disabling usb stack sounds like means to goal, not the goal itself). ron -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
Re: [coreboot] disabling bios usb stack
disabling the usb stack is the goal in this case. ron On Mon, Aug 25, 2014 at 2:32 PM, Vladimir 'φ-coder/phcoder' Serbinenko phco...@gmail.com wrote: On 25.08.2014 23:28, ron minnich wrote: A friend asks me how to disable the usb stack in his bios. I have no clue, anyone? Doesn't sound like end goal. But I'd go through setup menu to see if something fits his *end* goal (disabling usb stack sounds like means to goal, not the goal itself). ron -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
