2015-05-05 22:08 GMT+02:00 Jean Delvare <jdelvare(a)suse.de>de>:
Le Sunday 03 May 2015 à 00:33 +0200, Thibaut Verron a écrit :
I am a tumbleweed user, and I have recently
(since 20150421 or
20150422) been having issues with my laptop's CPU overheating. Most of
the times, the fan does not change speed when the temperature
increases, and I cannot control its speed manually with pwm1_enable
set to 1.
I reported it on the factory mailing list, and together we could rule
out the possibility of a hardware failure (most likely dust on the
fan). In particular, through some (seemingly) random changes, I could
get the fan to work under manual control. This setting does not appear
to be reliably persistent upon reboot, but it proves that the fan can
still spin fast enough to cool down the CPU, when the OS has full
control on its speed.
The setting I have to mess with to reactivate the fan when it stops
working is the "thermal.off=1" parameter of the kernel. I would like
to be more accurate, but I can't : in the past few days, I have
"reactivated" the fan control twice, and as far as I can tell the
procedure was not the same (and the same procedure did not yield the
same consequences every time).
For reference, the factory thread is here:
I read this thread in part, and here are a few random comments:
* It is common that low fan speeds are reported incorrectly, this isn't
specific to your laptop. The reason is that fan speed control is
achieved by either PWM signal (most frequent) or by lowering the
voltage. In both cases the rotation feedback signal gets harder to
sense, and weaker signal translates to incorrect speed values being
reported. While inconvenient, it should in general not result in any
issue with thermal management.
Ok. Anyway, this part of the problem is not new, but now there is a
logical explanation for that too.
* If a recent kernel somehow messed up with your system, it is possible
that the problem survives warm reboots, including switching to other
operating systems or back to older kernels. I urge you to always _cold_
boot the machine before every test your perform. On laptops, cold
booting may require unplugging the AC adapter AND removing the battery
AND waiting for a couple minutes.
I did try that occasionally when "messing around with settings", but
you have a good point, I'll make that a habit. Rebooting vs turning
off and back on the computer (without unplugging it or waiting more
than 10s) did yield different results sometimes (but still nothing
* Your problems sound BIOS-related to me. In most BIOS there is an
option to load setup or failsafe defaults. If you didn't try that yet,
that would be worth trying.
I have tried restoring the bios to factory settings (the only thing my
bios seems to offer on this matter) and it didn't help. Thank you,
indeed I forgot to mention that on the other thread.
* If the previous advice doesn't help, it might be worth re-flashing the
BIOS even if no new version is available. If the BIOS code was somehow
corrupted, that would restore it.
I could try that, but I'm wary of taking this step: flashing a bios
with a computer that may shutdown because of critical temperature
sounds a bit dangerous. The first time I got issues of this kind, I
did update the bios (with the laptop directly on an indoor air
conditioner, I could do that because it was July), and it did not
help. But since nothing seems to be reproducible here, I might as well
try again now...
* When did you try manual fan speed control with pwm1_enable for the
last time? If you normally don't need to do that, it is entirely
possible that this has been broken for a longer time and you did not
notice and this issue is unrelated with your current troubles. OTOH is
the fan speed controller is hosed somehow, it wouldn't be all that
surprising if that affects both manual and automatic modes.
You have a good point of course, I usually only try manual control
when I have problems with automatic control, so last time must have
been in 2013, and I was not using openSUSE back then. It is quite
possible that manual control on my laptop has never been working
reliably with the openSUSE install.
But is it possible that manual control be broken without affecting
automatic control? I guess that's asking whether the kernel has a
lower-level access to the fan controls than what's exposed in the /sys
FWIW there was no recent change to the eeepc-laptop driver.
As a closing note, I don't know how old your model is, but it should be
noted that low-priced consumer hardware showing issues after 4-5 years
is nothing out of the ordinary. This may not be what's happening here...
but it may as well be "just" that.
That's right. But given that there was similar issues at age 1 (just
past warranty expiration... a critical point in a computer's lifetime,
I know), I would find it strange if this was a new issue. Of course,
it is still possible that the problems I had 3 and 2 years ago were
not merely software issues, but symptoms of a hardware failure that
was (temporarily) mitigated with software tweaks.
Thank you very much for your comments and suggestions. If nobody has
any other short-term suggestion, I'll try redownloading and flashing
the bios indeed.
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