Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On Thu, Nov 5, 2020 at 6:05 AM Brad Campbell wrote: > Appreciate the feedback. > > This would be the bare minimum based on the bits use in the original code. If > the original code worked "well enough" then this should be relatively safe. > > Tested on both machines I have access to. For the patch: Acked-by: Arnd Bergmann I'm glad you figured out something that works. This all looks reasonable and it makes much more sense than the original version that I tried to clean up just based on the code comments but without having access to hardware or documentation. Arnd
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 11/4/20 9:05 PM, Brad Campbell wrote: > On 5/11/20 3:43 pm, Guenter Roeck wrote: >> On 11/4/20 6:18 PM, Brad Campbell wrote: >>> On 5/11/20 12:20 am, Andreas Kemnade wrote: On Tue, 3 Nov 2020 16:56:32 +1100 Brad Campbell wrote: >>> > If anyone with a Mac having a conventional SMC and seeing issues on 5.9 > could test this it'd be appreciated. I'm not saying this code is > "correct", but it "works for me". > Seems to work here. dmesg | grep applesmc [ 1.350782] applesmc: key=561 fan=1 temp=33 index=33 acc=0 lux=2 kbd=1 [ 1.350922] applesmc applesmc.768: hwmon_device_register() is deprecated. Please convert the driver to use hwmon_device_register_with_info(). [ 17.748504] applesmc: wait_status looping 2: 0x4a, 0x4c, 0x4f [ 212.008952] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 213.033930] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 213.167908] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 219.087854] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e Tested it on top of 5.9 >>> >>> Much appreciated Andreas. >>> >>> I'm not entirely sure where to go from here. I'd really like some wider >>> testing before cleaning this up and submitting it. It puts extra checks & >>> constraints on the comms with the SMC that weren't there previously. >>> >>> I guess given there doesn't appear to have been a major outcry that the >>> driver broke in 5.9 might indicate that nobody is using it, or that it only >>> broke on certain machines? >>> >>> Can we get some guidance from the hwmon maintainers on what direction >>> they'd like to take? I don't really want to push this forward without >>> broader testing only to find it breaks a whole heap of machines on the >>> basis that it fixes mine. >>> >> >> Trick question ;-). >> >> I'd suggest to keep it simple. Your patch seems to be quite complicated >> and checks a lot of bits. Reducing that to a minimum would help limiting >> the risk that some of those bits are interpreted differently on other >> systems. >> >> Guenter >> >> > Appreciate the feedback. > > This would be the bare minimum based on the bits use in the original code. If > the original code worked "well enough" then this should be relatively safe. > Can you clean that up and submit as patch ? Thanks, Guenter
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 5/11/20 3:43 pm, Guenter Roeck wrote:
On 11/4/20 6:18 PM, Brad Campbell wrote:
On 5/11/20 12:20 am, Andreas Kemnade wrote:
On Tue, 3 Nov 2020 16:56:32 +1100
Brad Campbell wrote:
If anyone with a Mac having a conventional SMC and seeing issues on 5.9 could test this it'd be
appreciated. I'm not saying this code is "correct", but it "works for me".
Seems to work here.
dmesg | grep applesmc
[ 1.350782] applesmc: key=561 fan=1 temp=33 index=33 acc=0 lux=2 kbd=1
[ 1.350922] applesmc applesmc.768: hwmon_device_register() is deprecated.
Please convert the driver to use hwmon_device_register_with_info().
[ 17.748504] applesmc: wait_status looping 2: 0x4a, 0x4c, 0x4f
[ 212.008952] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e
[ 213.033930] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e
[ 213.167908] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e
[ 219.087854] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e
Tested it on top of 5.9
Much appreciated Andreas.
I'm not entirely sure where to go from here. I'd really like some wider testing
before cleaning this up and submitting it. It puts extra checks & constraints
on the comms with the SMC that weren't there previously.
I guess given there doesn't appear to have been a major outcry that the driver
broke in 5.9 might indicate that nobody is using it, or that it only broke on
certain machines?
Can we get some guidance from the hwmon maintainers on what direction they'd
like to take? I don't really want to push this forward without broader testing
only to find it breaks a whole heap of machines on the basis that it fixes mine.
Trick question ;-).
I'd suggest to keep it simple. Your patch seems to be quite complicated
and checks a lot of bits. Reducing that to a minimum would help limiting
the risk that some of those bits are interpreted differently on other
systems.
Guenter
Appreciate the feedback.
This would be the bare minimum based on the bits use in the original code. If the
original code worked "well enough" then this should be relatively safe.
Tested on both machines I have access to.
Regards,
Brad
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index a18887990f4a..22cc5122ce9a 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -42,6 +42,11 @@
#define APPLESMC_MAX_DATA_LENGTH 32
+/* Apple SMC status bits from VirtualSMC */
+#define SMC_STATUS_AWAITING_DATA 0x01 ///< Data waiting to be read
+#define SMC_STATUS_IB_CLOSED 0x02 /// A write is pending / will ignore
input
+#define SMC_STATUS_BUSY 0x04 ///< Busy in the middle of a command.
+
/* wait up to 128 ms for a status change. */
#define APPLESMC_MIN_WAIT 0x0010
#define APPLESMC_RETRY_WAIT0x0100
@@ -151,65 +156,77 @@ static unsigned int key_at_index;
static struct workqueue_struct *applesmc_led_wq;
/*
- * wait_read - Wait for a byte to appear on SMC port. Callers must
- * hold applesmc_lock.
+ * Wait for specific status bits with a mask on the SMC
+ * Used before and after writes, and before reads
*/
-static int wait_read(void)
+
+static int wait_status(u8 val, u8 mask)
{
unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC;
u8 status;
int us;
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
- usleep_range(us, us * 16);
status = inb(APPLESMC_CMD_PORT);
- /* read: wait for smc to settle */
- if (status & 0x01)
+ if ((status & mask) == val)
return 0;
/* timeout: give up */
if (time_after(jiffies, end))
break;
- }
-
- pr_warn("wait_read() fail: 0x%02x\n", status);
+ usleep_range(us, us * 16);
+ }
+ pr_warn("wait_status timeout: 0x%02x, 0x%02x, 0x%02x\n", status, val,
mask);
return -EIO;
}
/*
- * send_byte - Write to SMC port, retrying when necessary. Callers
+ * send_byte_data - Write to SMC data port. Callers
* must hold applesmc_lock.
+ * Parameter skip must be true on the last write of any
+ * command or it'll time out.
*/
-static int send_byte(u8 cmd, u16 port)
+
+static int send_byte_data(u8 cmd, u16 port, bool skip)
{
- u8 status;
- int us;
- unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC;
+ u8 wstat = SMC_STATUS_BUSY;
+ if (skip)
+ wstat = 0;
+ if (wait_status(SMC_STATUS_BUSY,
+ SMC_STATUS_BUSY | SMC_STATUS_IB_CLOSED))
+ goto fail;
outb(cmd, port);
- for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
- usleep_range(us, us * 16);
- status = inb(APPLESMC_CMD_PORT);
- /* write: wait for smc to settle */
- if (status & 0x02)
- continue;
- /* ready: cmd accepted, return */
-
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 11/4/20 6:18 PM, Brad Campbell wrote: > On 5/11/20 12:20 am, Andreas Kemnade wrote: >> On Tue, 3 Nov 2020 16:56:32 +1100 >> Brad Campbell wrote: > >>> If anyone with a Mac having a conventional SMC and seeing issues on 5.9 >>> could test this it'd be appreciated. I'm not saying this code is "correct", >>> but it "works for me". >>> >> Seems to work here. >> dmesg | grep applesmc >> >> [ 1.350782] applesmc: key=561 fan=1 temp=33 index=33 acc=0 lux=2 kbd=1 >> [ 1.350922] applesmc applesmc.768: hwmon_device_register() is deprecated. >> Please convert the driver to use hwmon_device_register_with_info(). >> [ 17.748504] applesmc: wait_status looping 2: 0x4a, 0x4c, 0x4f >> [ 212.008952] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e >> [ 213.033930] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e >> [ 213.167908] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e >> [ 219.087854] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e >> >> Tested it on top of 5.9 > > Much appreciated Andreas. > > I'm not entirely sure where to go from here. I'd really like some wider > testing before cleaning this up and submitting it. It puts extra checks & > constraints on the comms with the SMC that weren't there previously. > > I guess given there doesn't appear to have been a major outcry that the > driver broke in 5.9 might indicate that nobody is using it, or that it only > broke on certain machines? > > Can we get some guidance from the hwmon maintainers on what direction they'd > like to take? I don't really want to push this forward without broader > testing only to find it breaks a whole heap of machines on the basis that it > fixes mine. > Trick question ;-). I'd suggest to keep it simple. Your patch seems to be quite complicated and checks a lot of bits. Reducing that to a minimum would help limiting the risk that some of those bits are interpreted differently on other systems. Guenter
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 5/11/20 1:18 pm, Brad Campbell wrote:
I'm not entirely sure where to go from here. I'd really like some wider testing
before cleaning this up and submitting it. It puts extra checks & constraints
on the comms with the SMC that weren't there previously.
I guess given there doesn't appear to have been a major outcry that the driver
broke in 5.9 might indicate that nobody is using it, or that it only broke on
certain machines?
Can we get some guidance from the hwmon maintainers on what direction they'd
like to take? I don't really want to push this forward without broader testing
only to find it breaks a whole heap of machines on the basis that it fixes mine.
I managed to find an iMac 12,2 to test with. Had to remove the check for bit
0x40 (that machine sets bit 0x10). Updated patch with debugging code removed
attached for comment.
Regards,
Brad
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index a18887990f4a..2e7dc820bb2e 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -42,6 +42,16 @@
#define APPLESMC_MAX_DATA_LENGTH 32
+/* Apple SMC status bits from VirtualSMC */
+#define SMC_STATUS_AWAITING_DATA 0x01 ///< Data waiting to be read
+#define SMC_STATUS_IB_CLOSED 0x02 /// A write is pending / will ignore
input
+#define SMC_STATUS_BUSY 0x04 ///< Busy in the middle of a command.
+#define SMC_STATUS_GOT_COMMAND0x08 ///< The last input was a command.
+#define SMC_STATUS_UKN_0x16 0x10
+#define SMC_STATUS_KEY_DONE 0x20
+#define SMC_STATUS_READY 0x40 // Ready to work
+#define SMC_STATUS_UKN_0x80 0x80 // error
+
/* wait up to 128 ms for a status change. */
#define APPLESMC_MIN_WAIT 0x0010
#define APPLESMC_RETRY_WAIT0x0100
@@ -151,65 +161,78 @@ static unsigned int key_at_index;
static struct workqueue_struct *applesmc_led_wq;
/*
- * wait_read - Wait for a byte to appear on SMC port. Callers must
- * hold applesmc_lock.
+ * Wait for specific status bits with a mask on the SMC
+ * Used before and after writes, and before reads
*/
-static int wait_read(void)
+
+static int wait_status(u8 val, u8 mask)
{
unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC;
u8 status;
int us;
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
- usleep_range(us, us * 16);
status = inb(APPLESMC_CMD_PORT);
- /* read: wait for smc to settle */
- if (status & 0x01)
+ if ((status & mask) == val)
return 0;
/* timeout: give up */
if (time_after(jiffies, end))
break;
- }
-
- pr_warn("wait_read() fail: 0x%02x\n", status);
+ usleep_range(us, us * 16);
+ }
+ pr_warn("wait_status timeout: 0x%02x, 0x%02x, 0x%02x\n", status, val,
mask);
return -EIO;
}
/*
- * send_byte - Write to SMC port, retrying when necessary. Callers
+ * send_byte_data - Write to SMC data port. Callers
* must hold applesmc_lock.
+ * Parameter skip must be true on the last write of any
+ * command or it'll time out.
*/
-static int send_byte(u8 cmd, u16 port)
+
+static int send_byte_data(u8 cmd, u16 port, bool skip)
{
- u8 status;
- int us;
- unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC;
+ u8 wstat = SMC_STATUS_BUSY;
+ if (skip)
+ wstat = 0;
+ if (wait_status(SMC_STATUS_BUSY,
+ SMC_STATUS_BUSY | SMC_STATUS_IB_CLOSED))
+ goto fail;
outb(cmd, port);
- for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
- usleep_range(us, us * 16);
- status = inb(APPLESMC_CMD_PORT);
- /* write: wait for smc to settle */
- if (status & 0x02)
- continue;
- /* ready: cmd accepted, return */
- if (status & 0x04)
- return 0;
- /* timeout: give up */
- if (time_after(jiffies, end))
- break;
- /* busy: long wait and resend */
- udelay(APPLESMC_RETRY_WAIT);
- outb(cmd, port);
- }
-
- pr_warn("send_byte(0x%02x, 0x%04x) fail: 0x%02x\n", cmd, port, status);
+ if (!wait_status(wstat,
+ SMC_STATUS_READY | SMC_STATUS_GOT_COMMAND | SMC_STATUS_BUSY |
SMC_STATUS_IB_CLOSED))
+ return 0;
+fail:
+ pr_warn("send_byte_data(0x%02x, 0x%04x) fail\n", cmd,
APPLESMC_CMD_PORT);
return -EIO;
}
+/*
+ * send_command - Write a command to the SMC. Callers must hold applesmc_lock.
+ * If SMC is in undefined state, any new command write resets the state
machine.
+ */
+
static int send_command(u8 cmd)
{
- return send_byte(cmd, APPLESMC_CMD_PORT);
+ u8 status;
+
+ if (wait_status(0,
+ SMC_STATUS_IB_CLOSED)) {
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 5/11/20 12:20 am, Andreas Kemnade wrote: On Tue, 3 Nov 2020 16:56:32 +1100 Brad Campbell wrote: If anyone with a Mac having a conventional SMC and seeing issues on 5.9 could test this it'd be appreciated. I'm not saying this code is "correct", but it "works for me". Seems to work here. dmesg | grep applesmc [1.350782] applesmc: key=561 fan=1 temp=33 index=33 acc=0 lux=2 kbd=1 [1.350922] applesmc applesmc.768: hwmon_device_register() is deprecated. Please convert the driver to use hwmon_device_register_with_info(). [ 17.748504] applesmc: wait_status looping 2: 0x4a, 0x4c, 0x4f [ 212.008952] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 213.033930] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 213.167908] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 219.087854] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e Tested it on top of 5.9 Much appreciated Andreas. I'm not entirely sure where to go from here. I'd really like some wider testing before cleaning this up and submitting it. It puts extra checks & constraints on the comms with the SMC that weren't there previously. I guess given there doesn't appear to have been a major outcry that the driver broke in 5.9 might indicate that nobody is using it, or that it only broke on certain machines? Can we get some guidance from the hwmon maintainers on what direction they'd like to take? I don't really want to push this forward without broader testing only to find it breaks a whole heap of machines on the basis that it fixes mine. Regards, Brad
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On Tue, 3 Nov 2020 16:56:32 +1100 Brad Campbell wrote: > On 3/11/20 10:56 am, Brad Campbell wrote: > > > > > I've examined the code in VirtualSMC and I'm not convinced we were not > > waiting on the wrong bits. > > > > #define SMC_STATUS_AWAITING_DATA BIT0 ///< Ready to read data. > > #define SMC_STATUS_IB_CLOSED BIT1 /// A write is pending. > > #define SMC_STATUS_BUSY BIT2 ///< Busy processing a command. > > #define SMC_STATUS_GOT_COMMAND BIT3 ///< The last input was a command. > > #define SMC_STATUS_UKN_0x16 BIT4 > > #define SMC_STATUS_KEY_DONE BIT5 > > #define SMC_STATUS_READY BIT6 // Ready to work > > #define SMC_STATUS_UKN_0x80 BIT7 // error > > > > Any chance you could try this patch? It's ugly, hacked together and > > currently fairly undocumented, but if it works I'll figure out how to clean > > it up (suggestions welcome). > > It works on my MacbookPro 11,1. > > I had some time so I spent a bit of time refactoring and trying to clarify > the magic numbers. > > I also did some fuzzing of the SMC and figured out where we can loosen the > masks. > This has some debug code in it to identify if any wait loops exceed 1 loop > and if the SMC is reporting anything other than a clear "I'm waiting" prior > to each command. > > You might see some of these : > [ 51.316202] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e > [ 60.002547] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e > [ 60.130754] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e > > I did some heavy tests and found that with the delays at the bottom of the > loop about 50% of calls required no delay at all before a read or write and > the other 50% require a single delay. > I can count on one hand the number of times it's exceeded 1 loop, and the max > thus far has been 5 loops. > That matches my experience. The only delay is at the end of the command. Critcal seems to be that there is not too much delay in between. [...] > If anyone with a Mac having a conventional SMC and seeing issues on 5.9 could > test this it'd be appreciated. I'm not saying this code is "correct", but it > "works for me". > Seems to work here. dmesg | grep applesmc [1.350782] applesmc: key=561 fan=1 temp=33 index=33 acc=0 lux=2 kbd=1 [1.350922] applesmc applesmc.768: hwmon_device_register() is deprecated. Please convert the driver to use hwmon_device_register_with_info(). [ 17.748504] applesmc: wait_status looping 2: 0x4a, 0x4c, 0x4f [ 212.008952] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 213.033930] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 213.167908] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 219.087854] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e Tested it on top of 5.9 Regards, Andreas
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 3/11/20 10:56 am, Brad Campbell wrote: I've examined the code in VirtualSMC and I'm not convinced we were not waiting on the wrong bits. #define SMC_STATUS_AWAITING_DATA BIT0 ///< Ready to read data. #define SMC_STATUS_IB_CLOSED BIT1 /// A write is pending. #define SMC_STATUS_BUSY BIT2 ///< Busy processing a command. #define SMC_STATUS_GOT_COMMAND BIT3 ///< The last input was a command. #define SMC_STATUS_UKN_0x16 BIT4 #define SMC_STATUS_KEY_DONE BIT5 #define SMC_STATUS_READY BIT6 // Ready to work #define SMC_STATUS_UKN_0x80 BIT7 // error Any chance you could try this patch? It's ugly, hacked together and currently fairly undocumented, but if it works I'll figure out how to clean it up (suggestions welcome). It works on my MacbookPro 11,1. I had some time so I spent a bit of time refactoring and trying to clarify the magic numbers. I also did some fuzzing of the SMC and figured out where we can loosen the masks. This has some debug code in it to identify if any wait loops exceed 1 loop and if the SMC is reporting anything other than a clear "I'm waiting" prior to each command. You might see some of these : [ 51.316202] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 60.002547] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e [ 60.130754] applesmc: wait_status looping 2: 0x44, 0x40, 0x4e I did some heavy tests and found that with the delays at the bottom of the loop about 50% of calls required no delay at all before a read or write and the other 50% require a single delay. I can count on one hand the number of times it's exceeded 1 loop, and the max thus far has been 5 loops. We've been treating bit 0x04 as an ack, but from my testing on the machine and what I've seen in the SMC emulator code it actually means "I'm busy in the middle of a command". Bit 0x02 seems to mean "I'm doing something and I *will* ignore anything you send me". Bit 0x08 means "The last thing I got was a valid command, so start sending me data". By testing and waiting for 0x02 to clear before sending or reading I haven't seen any need for retries. On my unit bit 0x40 is always active. It may not be on others. The emulator calls it a status ready, so it's tested for but that is consolidated in wait_status so it can be commented out if it doesn't work on your machine. The thing with bit 0x04 is the SMC clears it when it's no longer busy. So the last byte of data sent for a command sees it clear that bit. That explains the timeouts but the command still works. As far as the SMC is concerned it's got all the data and gone off to do its thing, but applesmc was waiting for the bit to be set. When it's in the middle of a command (from the first command byte until the last data byte is received) I've never seen bit 0x04 cleared, so using it as an "ack" works, but as said upward in the thread "probably by accident". So this code tests for an "idle" SMC before it sends a command. In this context idle just means bit 0x02 isn't set. If the SMC gets into an undefined state it can leave other bits set, but a new write with a valid command will reset the internal state machine and bring it back into line. Bit 0x08 should always be set after it has received a valid command. I've gone belt and braces by checking the status before and after each command, but with the intention of trying to catch and log anything that goes awry. Like I said above, in 50% of cases I see zero delays required so I thought testing before the delay was a worthwhile win. If anyone with a Mac having a conventional SMC and seeing issues on 5.9 could test this it'd be appreciated. I'm not saying this code is "correct", but it "works for me". If anyone actually knows what they're doing and wants to "correct" me, it'd be appreciated also. Regards, Brad diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c index a18887990f4a..abb06fbe7bc1 100644 --- a/drivers/hwmon/applesmc.c +++ b/drivers/hwmon/applesmc.c @@ -42,6 +42,16 @@ #define APPLESMC_MAX_DATA_LENGTH 32 +/* Apple SMC status bits */ +#define SMC_STATUS_AWAITING_DATA 0x01 ///< Data waiting to be read +#define SMC_STATUS_IB_CLOSED 0x02 /// A write is pending / will ignore input +#define SMC_STATUS_BUSY 0x04 ///< Busy in the middle of a command. +#define SMC_STATUS_GOT_COMMAND0x08 ///< The last input was a command. +#define SMC_STATUS_UKN_0x16 0x10 +#define SMC_STATUS_KEY_DONE 0x20 +#define SMC_STATUS_READY 0x40 // Ready to work +#define SMC_STATUS_UKN_0x80 0x80 // error + /* wait up to 128 ms for a status change. */ #define APPLESMC_MIN_WAIT 0x0010 #define APPLESMC_RETRY_WAIT0x0100 @@ -151,65 +161,88 @@ static unsigned int key_at_index; static struct workqueue_struct *applesmc_led_wq; /* - * wait_read - Wait for a byte to appear on SMC port. Callers must - * hold applesmc_lock. + * Wait for specific status bits with a mask on the
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 6/10/20 6:02 pm, Andreas Kemnade wrote:
On Thu, 1 Oct 2020 21:07:51 -0700
Guenter Roeck wrote:
On 10/1/20 3:22 PM, Andreas Kemnade wrote:
On Wed, 30 Sep 2020 22:00:09 +0200
Arnd Bergmann wrote:
On Wed, Sep 30, 2020 at 6:44 PM Guenter Roeck wrote:
On Wed, Sep 30, 2020 at 10:54:42AM +0200, Andreas Kemnade wrote:
Hi,
after the $subject patch I get lots of errors like this:
For reference, this refers to commit fff2d0f701e6 ("hwmon: (applesmc)
avoid overlong udelay()").
[ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40
[ 120.378621] applesmc: LKSB: write data fail
[ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40
[ 120.512787] applesmc: LKSB: write data fail
CPU sticks at low speed and no fan is turning on.
Reverting this patch on top of 5.9-rc6 solves this problem.
Some information from dmidecode:
Base Board Information
Manufacturer: Apple Inc.
Product Name: Mac-7DF21CB3ED6977E5
Version: MacBookAir6,2
Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple ROM
Version. Model: …,
Handle 0x0020, DMI type 11, 5 bytes
OEM Strings
String 1: Apple ROM Version. Model:MBA61. EFI Version:
122.0.0
String 2: .0.0. Built by: root@saumon. Date: Wed Jun 10
18:
String 3: 10:36 PDT 2020. Revision: 122 (B). ROM Version:
F000_B
String 4: 00. Build Type: Official Build, Release. Compiler:
Appl
String 5: e clang version 3.0 (tags/Apple/clang-211.10.1) (based on
LLVM
String 6: 3.0svn).
Writing to things in /sys/devices/platform/applesmc.768 gives also the
said errors.
But writing 1 to fan1_maunal and 5000 to fan1_output turns the fan on
despite error messages.
Not really sure what to do here. I could revert the patch, but then we'd gain
clang compile failures. Arnd, any idea ?
It seems that either I made a mistake in the conversion and it sleeps for
less time than before, or my assumption was wrong that converting a delay to
a sleep is safe here.
The error message indicates that the write fails, not the read, so that
is what I'd look at first. Right away I can see that the maximum time to
retry is only half of what it used to be, as we used to wait for
0x10, 0x20, 0x40, 0x80, ..., 0x2 microseconds for a total of
0x3fff0 microseconds (262ms), while my patch went with the 131ms
total delay based on the comment saying "/* wait up to 128 ms for a
status change. */".
Yes, that is also what I read from the code. I just thought there must
be something simple, which just needs a short look from another pair of
eyes.
Since there is sleeping wait, I see no reason the timeout couldn't
be extended a lot, e.g. to a second, as in
#define APPLESMC_MAX_WAIT 0x10
If that doesn't work, I'd try using mdelay() in place of
usleep_range(), such as
mdelay(DIV_ROUND_UP(us, USEC_PER_MSEC)));
This adds back a really nasty latency, but it should avoid the
compile-time problem.
Andreas, can you try those two things? (one at a time,
not both)
Ok, I tried. None of them works. I rechecked my work and created real
git commits out of them and CONFIG_LOCALVERSION_AUTO is also set so
the usual stupid things are rules out.
In detail:
On top of 5.9-rc6 + *reverted* patch:
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index fd99c9df8a00..2a9bd7f2b71b 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -45,7 +45,7 @@
/* wait up to 128 ms for a status change. */
#define APPLESMC_MIN_WAIT 0x0010
#define APPLESMC_RETRY_WAIT 0x0100
-#define APPLESMC_MAX_WAIT 0x2
+#define APPLESMC_MAX_WAIT 0x8000
#define APPLESMC_READ_CMD 0x10
#define APPLESMC_WRITE_CMD0x11
Oh man, that code is so badlys broken.
send_byte() repeats sending the data if it was not immediately successful.
That is done for both data and commands. Effectively that happens if
the command is not immediately accepted. However, send_argument()
clearly assumes that each data byte is sent exactly once. Sending
it more than once will mess up the key that is supposed to be sent.
The Apple SMC emulation code in qemu confirms that data bytes can not
be written more than once.
Of course, theoretically it may be that the first data byte was not
accepted (after all, the ACK bit is not set), but the ACK bit is
not checked again after udelay(APPLESMC_RETRY_WAIT), so it may
well have been set in the 256 uS between its check and re-writing
the data.
In other words, this entire code only works accidentally to start with.
If you like, you could play around with the code and find out if and
when exactly bit 1 (busy) is set, if and when bit 2 (ack) is set, and
if and when any other bit is set. We could also try to read port 0x31e
(the error port). Maybe the we can figure out what the error actually
is. But then I don't really know what we could do with that information.
Smoe research results: the
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On Thu, 1 Oct 2020 21:07:51 -0700
Guenter Roeck wrote:
> On 10/1/20 3:22 PM, Andreas Kemnade wrote:
> > On Wed, 30 Sep 2020 22:00:09 +0200
> > Arnd Bergmann wrote:
> >
> >> On Wed, Sep 30, 2020 at 6:44 PM Guenter Roeck wrote:
> >>>
> >>> On Wed, Sep 30, 2020 at 10:54:42AM +0200, Andreas Kemnade wrote:
> Hi,
>
> after the $subject patch I get lots of errors like this:
> >>>
> >>> For reference, this refers to commit fff2d0f701e6 ("hwmon: (applesmc)
> >>> avoid overlong udelay()").
> >>>
> [ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> [ 120.378621] applesmc: LKSB: write data fail
> [ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> [ 120.512787] applesmc: LKSB: write data fail
>
> CPU sticks at low speed and no fan is turning on.
> Reverting this patch on top of 5.9-rc6 solves this problem.
>
> Some information from dmidecode:
>
> Base Board Information
> Manufacturer: Apple Inc.
> Product Name: Mac-7DF21CB3ED6977E5
> Version: MacBookAir6,2
>
> Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple
> ROM Version. Model: …,
> Handle 0x0020, DMI type 11, 5 bytes
> OEM Strings
> String 1: Apple ROM Version. Model:MBA61. EFI Version:
> 122.0.0
> String 2: .0.0. Built by: root@saumon. Date: Wed
> Jun 10 18:
> String 3: 10:36 PDT 2020. Revision: 122 (B). ROM
> Version: F000_B
> String 4: 00. Build Type: Official Build, Release. Compiler:
> Appl
> String 5: e clang version 3.0 (tags/Apple/clang-211.10.1) (based
> on LLVM
> String 6: 3.0svn).
>
> Writing to things in /sys/devices/platform/applesmc.768 gives also the
> said errors.
> But writing 1 to fan1_maunal and 5000 to fan1_output turns the fan on
> despite error messages.
>
> >>> Not really sure what to do here. I could revert the patch, but then we'd
> >>> gain
> >>> clang compile failures. Arnd, any idea ?
> >>
> >> It seems that either I made a mistake in the conversion and it sleeps for
> >> less time than before, or my assumption was wrong that converting a delay
> >> to
> >> a sleep is safe here.
> >>
> >> The error message indicates that the write fails, not the read, so that
> >> is what I'd look at first. Right away I can see that the maximum time to
> >> retry is only half of what it used to be, as we used to wait for
> >> 0x10, 0x20, 0x40, 0x80, ..., 0x2 microseconds for a total of
> >> 0x3fff0 microseconds (262ms), while my patch went with the 131ms
> >> total delay based on the comment saying "/* wait up to 128 ms for a
> >> status change. */".
> >>
> > Yes, that is also what I read from the code. I just thought there must
> > be something simple, which just needs a short look from another pair of
> > eyes.
> >
> >> Since there is sleeping wait, I see no reason the timeout couldn't
> >> be extended a lot, e.g. to a second, as in
> >>
> >> #define APPLESMC_MAX_WAIT 0x10
> >>
> >> If that doesn't work, I'd try using mdelay() in place of
> >> usleep_range(), such as
> >>
> >>mdelay(DIV_ROUND_UP(us, USEC_PER_MSEC)));
> >>
> >> This adds back a really nasty latency, but it should avoid the
> >> compile-time problem.
> >>
> >> Andreas, can you try those two things? (one at a time,
> >> not both)
> >
> > Ok, I tried. None of them works. I rechecked my work and created real
> > git commits out of them and CONFIG_LOCALVERSION_AUTO is also set so
> > the usual stupid things are rules out.
> > In detail:
> > On top of 5.9-rc6 + *reverted* patch:
> > diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
> > index fd99c9df8a00..2a9bd7f2b71b 100644
> > --- a/drivers/hwmon/applesmc.c
> > +++ b/drivers/hwmon/applesmc.c
> > @@ -45,7 +45,7 @@
> > /* wait up to 128 ms for a status change. */
> > #define APPLESMC_MIN_WAIT 0x0010
> > #define APPLESMC_RETRY_WAIT0x0100
> > -#define APPLESMC_MAX_WAIT 0x2
> > +#define APPLESMC_MAX_WAIT 0x8000
> >
> > #define APPLESMC_READ_CMD 0x10
> > #define APPLESMC_WRITE_CMD 0x11
> >
>
> Oh man, that code is so badlys broken.
>
> send_byte() repeats sending the data if it was not immediately successful.
> That is done for both data and commands. Effectively that happens if
> the command is not immediately accepted. However, send_argument()
> clearly assumes that each data byte is sent exactly once. Sending
> it more than once will mess up the key that is supposed to be sent.
> The Apple SMC emulation code in qemu confirms that data bytes can not
> be written more than once.
>
> Of course, theoretically it may be that the first data byte was not
> accepted (after all, the ACK bit is not set), but the ACK bit is
> not checked again after udelay(APPLESMC_RETRY_WAIT), so it may
>
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On 10/1/20 3:22 PM, Andreas Kemnade wrote:
> On Wed, 30 Sep 2020 22:00:09 +0200
> Arnd Bergmann wrote:
>
>> On Wed, Sep 30, 2020 at 6:44 PM Guenter Roeck wrote:
>>>
>>> On Wed, Sep 30, 2020 at 10:54:42AM +0200, Andreas Kemnade wrote:
Hi,
after the $subject patch I get lots of errors like this:
>>>
>>> For reference, this refers to commit fff2d0f701e6 ("hwmon: (applesmc)
>>> avoid overlong udelay()").
>>>
[ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40
[ 120.378621] applesmc: LKSB: write data fail
[ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40
[ 120.512787] applesmc: LKSB: write data fail
CPU sticks at low speed and no fan is turning on.
Reverting this patch on top of 5.9-rc6 solves this problem.
Some information from dmidecode:
Base Board Information
Manufacturer: Apple Inc.
Product Name: Mac-7DF21CB3ED6977E5
Version: MacBookAir6,2
Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple
ROM Version. Model: …,
Handle 0x0020, DMI type 11, 5 bytes
OEM Strings
String 1: Apple ROM Version. Model:MBA61. EFI Version:
122.0.0
String 2: .0.0. Built by: root@saumon. Date: Wed Jun
10 18:
String 3: 10:36 PDT 2020. Revision: 122 (B). ROM Version:
F000_B
String 4: 00. Build Type: Official Build, Release. Compiler:
Appl
String 5: e clang version 3.0 (tags/Apple/clang-211.10.1) (based
on LLVM
String 6: 3.0svn).
Writing to things in /sys/devices/platform/applesmc.768 gives also the
said errors.
But writing 1 to fan1_maunal and 5000 to fan1_output turns the fan on
despite error messages.
>>> Not really sure what to do here. I could revert the patch, but then we'd
>>> gain
>>> clang compile failures. Arnd, any idea ?
>>
>> It seems that either I made a mistake in the conversion and it sleeps for
>> less time than before, or my assumption was wrong that converting a delay to
>> a sleep is safe here.
>>
>> The error message indicates that the write fails, not the read, so that
>> is what I'd look at first. Right away I can see that the maximum time to
>> retry is only half of what it used to be, as we used to wait for
>> 0x10, 0x20, 0x40, 0x80, ..., 0x2 microseconds for a total of
>> 0x3fff0 microseconds (262ms), while my patch went with the 131ms
>> total delay based on the comment saying "/* wait up to 128 ms for a
>> status change. */".
>>
> Yes, that is also what I read from the code. I just thought there must
> be something simple, which just needs a short look from another pair of
> eyes.
>
>> Since there is sleeping wait, I see no reason the timeout couldn't
>> be extended a lot, e.g. to a second, as in
>>
>> #define APPLESMC_MAX_WAIT 0x10
>>
>> If that doesn't work, I'd try using mdelay() in place of
>> usleep_range(), such as
>>
>>mdelay(DIV_ROUND_UP(us, USEC_PER_MSEC)));
>>
>> This adds back a really nasty latency, but it should avoid the
>> compile-time problem.
>>
>> Andreas, can you try those two things? (one at a time,
>> not both)
>
> Ok, I tried. None of them works. I rechecked my work and created real
> git commits out of them and CONFIG_LOCALVERSION_AUTO is also set so
> the usual stupid things are rules out.
> In detail:
> On top of 5.9-rc6 + *reverted* patch:
> diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
> index fd99c9df8a00..2a9bd7f2b71b 100644
> --- a/drivers/hwmon/applesmc.c
> +++ b/drivers/hwmon/applesmc.c
> @@ -45,7 +45,7 @@
> /* wait up to 128 ms for a status change. */
> #define APPLESMC_MIN_WAIT0x0010
> #define APPLESMC_RETRY_WAIT 0x0100
> -#define APPLESMC_MAX_WAIT0x2
> +#define APPLESMC_MAX_WAIT0x8000
>
> #define APPLESMC_READ_CMD0x10
> #define APPLESMC_WRITE_CMD 0x11
>
Oh man, that code is so badlys broken.
send_byte() repeats sending the data if it was not immediately successful.
That is done for both data and commands. Effectively that happens if
the command is not immediately accepted. However, send_argument()
clearly assumes that each data byte is sent exactly once. Sending
it more than once will mess up the key that is supposed to be sent.
The Apple SMC emulation code in qemu confirms that data bytes can not
be written more than once.
Of course, theoretically it may be that the first data byte was not
accepted (after all, the ACK bit is not set), but the ACK bit is
not checked again after udelay(APPLESMC_RETRY_WAIT), so it may
well have been set in the 256 uS between its check and re-writing
the data.
In other words, this entire code only works accidentally to start with.
If you like, you could play around with the code and find out if and
when exactly bit 1 (busy) is set, if and when bit 2 (ack) is set, and
if and when any other bit is set.
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On Wed, 30 Sep 2020 22:00:09 +0200
Arnd Bergmann wrote:
> On Wed, Sep 30, 2020 at 6:44 PM Guenter Roeck wrote:
> >
> > On Wed, Sep 30, 2020 at 10:54:42AM +0200, Andreas Kemnade wrote:
> > > Hi,
> > >
> > > after the $subject patch I get lots of errors like this:
> >
> > For reference, this refers to commit fff2d0f701e6 ("hwmon: (applesmc)
> > avoid overlong udelay()").
> >
> > > [ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> > > [ 120.378621] applesmc: LKSB: write data fail
> > > [ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> > > [ 120.512787] applesmc: LKSB: write data fail
> > >
> > > CPU sticks at low speed and no fan is turning on.
> > > Reverting this patch on top of 5.9-rc6 solves this problem.
> > >
> > > Some information from dmidecode:
> > >
> > > Base Board Information
> > > Manufacturer: Apple Inc.
> > > Product Name: Mac-7DF21CB3ED6977E5
> > > Version: MacBookAir6,2
> > >
> > > Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple
> > > ROM Version. Model: …,
> > > Handle 0x0020, DMI type 11, 5 bytes
> > > OEM Strings
> > > String 1: Apple ROM Version. Model:MBA61. EFI Version:
> > > 122.0.0
> > > String 2: .0.0. Built by: root@saumon. Date: Wed
> > > Jun 10 18:
> > > String 3: 10:36 PDT 2020. Revision: 122 (B). ROM Version:
> > > F000_B
> > > String 4: 00. Build Type: Official Build, Release. Compiler:
> > >Appl
> > > String 5: e clang version 3.0 (tags/Apple/clang-211.10.1) (based
> > > on LLVM
> > > String 6: 3.0svn).
> > >
> > > Writing to things in /sys/devices/platform/applesmc.768 gives also the
> > > said errors.
> > > But writing 1 to fan1_maunal and 5000 to fan1_output turns the fan on
> > > despite error messages.
> > >
> > Not really sure what to do here. I could revert the patch, but then we'd
> > gain
> > clang compile failures. Arnd, any idea ?
>
> It seems that either I made a mistake in the conversion and it sleeps for
> less time than before, or my assumption was wrong that converting a delay to
> a sleep is safe here.
>
> The error message indicates that the write fails, not the read, so that
> is what I'd look at first. Right away I can see that the maximum time to
> retry is only half of what it used to be, as we used to wait for
> 0x10, 0x20, 0x40, 0x80, ..., 0x2 microseconds for a total of
> 0x3fff0 microseconds (262ms), while my patch went with the 131ms
> total delay based on the comment saying "/* wait up to 128 ms for a
> status change. */".
>
Yes, that is also what I read from the code. I just thought there must
be something simple, which just needs a short look from another pair of
eyes.
> Since there is sleeping wait, I see no reason the timeout couldn't
> be extended a lot, e.g. to a second, as in
>
> #define APPLESMC_MAX_WAIT 0x10
>
> If that doesn't work, I'd try using mdelay() in place of
> usleep_range(), such as
>
>mdelay(DIV_ROUND_UP(us, USEC_PER_MSEC)));
>
> This adds back a really nasty latency, but it should avoid the
> compile-time problem.
>
> Andreas, can you try those two things? (one at a time,
> not both)
Ok, I tried. None of them works. I rechecked my work and created real
git commits out of them and CONFIG_LOCALVERSION_AUTO is also set so
the usual stupid things are rules out.
In detail:
On top of 5.9-rc6 + *reverted* patch:
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index fd99c9df8a00..2a9bd7f2b71b 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -45,7 +45,7 @@
/* wait up to 128 ms for a status change. */
#define APPLESMC_MIN_WAIT 0x0010
#define APPLESMC_RETRY_WAIT0x0100
-#define APPLESMC_MAX_WAIT 0x2
+#define APPLESMC_MAX_WAIT 0x8000
#define APPLESMC_READ_CMD 0x10
#define APPLESMC_WRITE_CMD 0x11
--
2.20.1
-> no trouble found, but I have not tested very long, just some
sysfs writes.
On top of 5.9-rc6:
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index a18887990f4a..3b0108b75a24 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -161,7 +161,7 @@ static int wait_read(void)
int us;
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
- usleep_range(us, us * 16);
+ mdelay(DIV_ROUND_UP(us, USEC_PER_MSEC));
status = inb(APPLESMC_CMD_PORT);
/* read: wait for smc to settle */
if (status & 0x01)
@@ -187,7 +187,7 @@ static int send_byte(u8 cmd, u16 port)
outb(cmd, port);
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
- usleep_range(us, us * 16);
+ mdelay(DIV_ROUND_UP(us, USEC_PER_MSEC));
status = inb(APPLESMC_CMD_PORT);
/* write: wait for smc to settle */
if (status & 0x02)
--
2.20.1
-> write
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On Wed, Sep 30, 2020 at 6:44 PM Guenter Roeck wrote:
>
> On Wed, Sep 30, 2020 at 10:54:42AM +0200, Andreas Kemnade wrote:
> > Hi,
> >
> > after the $subject patch I get lots of errors like this:
>
> For reference, this refers to commit fff2d0f701e6 ("hwmon: (applesmc)
> avoid overlong udelay()").
>
> > [ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> > [ 120.378621] applesmc: LKSB: write data fail
> > [ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> > [ 120.512787] applesmc: LKSB: write data fail
> >
> > CPU sticks at low speed and no fan is turning on.
> > Reverting this patch on top of 5.9-rc6 solves this problem.
> >
> > Some information from dmidecode:
> >
> > Base Board Information
> > Manufacturer: Apple Inc.
> > Product Name: Mac-7DF21CB3ED6977E5
> > Version: MacBookAir6,2
> >
> > Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple ROM
> > Version. Model: …,
> > Handle 0x0020, DMI type 11, 5 bytes
> > OEM Strings
> > String 1: Apple ROM Version. Model:MBA61. EFI Version:
> > 122.0.0
> > String 2: .0.0. Built by: root@saumon. Date: Wed Jun
> > 10 18:
> > String 3: 10:36 PDT 2020. Revision: 122 (B). ROM Version:
> > F000_B
> > String 4: 00. Build Type: Official Build, Release. Compiler:
> > Appl
> > String 5: e clang version 3.0 (tags/Apple/clang-211.10.1) (based on
> > LLVM
> > String 6: 3.0svn).
> >
> > Writing to things in /sys/devices/platform/applesmc.768 gives also the
> > said errors.
> > But writing 1 to fan1_maunal and 5000 to fan1_output turns the fan on
> > despite error messages.
> >
> Not really sure what to do here. I could revert the patch, but then we'd gain
> clang compile failures. Arnd, any idea ?
It seems that either I made a mistake in the conversion and it sleeps for
less time than before, or my assumption was wrong that converting a delay to
a sleep is safe here.
The error message indicates that the write fails, not the read, so that
is what I'd look at first. Right away I can see that the maximum time to
retry is only half of what it used to be, as we used to wait for
0x10, 0x20, 0x40, 0x80, ..., 0x2 microseconds for a total of
0x3fff0 microseconds (262ms), while my patch went with the 131ms
total delay based on the comment saying "/* wait up to 128 ms for a
status change. */".
Since there is sleeping wait, I see no reason the timeout couldn't
be extended a lot, e.g. to a second, as in
#define APPLESMC_MAX_WAIT 0x10
If that doesn't work, I'd try using mdelay() in place of
usleep_range(), such as
mdelay(DIV_ROUND_UP(us, USEC_PER_MSEC)));
This adds back a really nasty latency, but it should avoid the
compile-time problem.
Andreas, can you try those two things? (one at a time,
not both)
Arnd
Re: [REGRESSION] hwmon: (applesmc) avoid overlong udelay()
On Wed, Sep 30, 2020 at 10:54:42AM +0200, Andreas Kemnade wrote:
> Hi,
>
> after the $subject patch I get lots of errors like this:
For reference, this refers to commit fff2d0f701e6 ("hwmon: (applesmc)
avoid overlong udelay()").
> [ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> [ 120.378621] applesmc: LKSB: write data fail
> [ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> [ 120.512787] applesmc: LKSB: write data fail
>
> CPU sticks at low speed and no fan is turning on.
> Reverting this patch on top of 5.9-rc6 solves this problem.
>
> Some information from dmidecode:
>
> Base Board Information
> Manufacturer: Apple Inc.
> Product Name: Mac-7DF21CB3ED6977E5
> Version: MacBookAir6,2
>
> Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple ROM
> Version. Model: …,
> Handle 0x0020, DMI type 11, 5 bytes
> OEM Strings
> String 1: Apple ROM Version. Model:MBA61. EFI Version:
> 122.0.0
> String 2: .0.0. Built by: root@saumon. Date: Wed Jun 10
> 18:
> String 3: 10:36 PDT 2020. Revision: 122 (B). ROM Version:
> F000_B
> String 4: 00. Build Type: Official Build, Release. Compiler:
> Appl
> String 5: e clang version 3.0 (tags/Apple/clang-211.10.1) (based on
> LLVM
> String 6: 3.0svn).
>
> Writing to things in /sys/devices/platform/applesmc.768 gives also the
> said errors.
> But writing 1 to fan1_maunal and 5000 to fan1_output turns the fan on
> despite error messages.
>
Not really sure what to do here. I could revert the patch, but then we'd gain
clang compile failures. Arnd, any idea ?
Guenter
[REGRESSION] hwmon: (applesmc) avoid overlong udelay()
Hi, after the $subject patch I get lots of errors like this: [ 120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40 [ 120.378621] applesmc: LKSB: write data fail [ 120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40 [ 120.512787] applesmc: LKSB: write data fail CPU sticks at low speed and no fan is turning on. Reverting this patch on top of 5.9-rc6 solves this problem. Some information from dmidecode: Base Board Information Manufacturer: Apple Inc. Product Name: Mac-7DF21CB3ED6977E5 Version: MacBookAir6,2 Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple ROM Version. Model: …, Handle 0x0020, DMI type 11, 5 bytes OEM Strings String 1: Apple ROM Version. Model:MBA61. EFI Version: 122.0.0 String 2: .0.0. Built by: root@saumon. Date: Wed Jun 10 18: String 3: 10:36 PDT 2020. Revision: 122 (B). ROM Version: F000_B String 4: 00. Build Type: Official Build, Release. Compiler: Appl String 5: e clang version 3.0 (tags/Apple/clang-211.10.1) (based on LLVM String 6: 3.0svn). Writing to things in /sys/devices/platform/applesmc.768 gives also the said errors. But writing 1 to fan1_maunal and 5000 to fan1_output turns the fan on despite error messages. Config used is: https://misc.andi.de1.cc/mac-config.gz Regards, Andreas
