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ASUS PU551LD, fan stuck at full speed after waking up from S3

DISCUSSION Martin Herkt 2 participants 3 messages May 29, 2015 – May 30, 2015

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My ASUS PU551LD laptop has a problem with its fan state when resuming from S3. In particular, the fan goes to full speed a second or two after waking up and cannot be reset without turning off the laptop. For example, rebooting to Windows and doing a suspend/resume cycle while the fan is in bad state will not reset it. I have observed this behavior with all kernel versions I have used on this laptop (oldest being 3.16, newest 4.1-rc5).

sensors(1) does not show any fans, but asus-nb-wmi exposes /sys/class/hwmon/hwmon2/pwm1, which shows values like 85 during normal operation but goes to the expected 255 when the fan is running at full speed after waking up from S3.

acpidump output: https://0x0.st/9Z.out

Not being a kernel dev (but knowing C), what can I do to help fix this issue?

#1 lore raw
Quoted 11 lines · Martin Herkt

My ASUS PU551LD laptop has a problem with its fan state when resuming from S3. In particular, the fan goes to full speed a second or two after waking up and cannot be reset without turning off the laptop. For example, rebooting to Windows and doing a suspend/resume cycle while the fan is in bad state will not reset it. I have observed this behavior with all kernel versions I have used on this laptop (oldest being 3.16, newest 4.1-rc5).

sensors(1) does not show any fans, but asus-nb-wmi exposes /sys/class/hwmon/hwmon2/pwm1, which shows values like 85 during normal operation but goes to the expected 255 when the fan is running at full speed after waking up from S3.

Can you please check if applying the patch at

https://patchwork.kernel.org/patch/6451241/

on top of 4.1-rc5 makes any difference?

Signature · 2 lines
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
#2 lore raw
Quoted 14 lines · On Saturday 30 May 2015 14:14:06 Rafael J. Wysocki wrote:
Quoted 8 lines · Martin Herkt

My ASUS PU551LD laptop has a problem with its fan state when resuming from S3. In particular, the fan goes to full speed a second or two after waking up and cannot be reset without turning off the laptop. For example, rebooting to Windows and doing a suspend/resume cycle while the fan is in bad state will not reset it. I have observed this behavior with all kernel versions I have used on this laptop (oldest being 3.16, newest 4.1-rc5).

Quoted 4 lines

sensors(1) does not show any fans, but asus-nb-wmi exposes /sys/class/hwmon/hwmon2/pwm1, which shows values like 85 during normal operation but goes to the expected 255 when the fan is running at full speed after waking up from S3.

Quoted 5 lines

Can you please check if applying the patch at

https://patchwork.kernel.org/patch/6451241/

on top of 4.1-rc5 makes any difference?

No, still happens with that patch.