[ltp] Re: X61s and fan speed < level 1

[Henrique de Moraes Holschuh]

On Mon, 31 Mar 2008, Günther Starnberger wrote:
> I just did one more test (running at "level auto" without doing any
> changes to the fan settings):

Ok.  Because that is something that you can complain to Lenovo, but if you
touch the fan controller settings, forget about it.

Oh, and you *are* running the latest firmware (BIOS/EC) I presume? If not,
update them and re-test.

> After booting, the fan was running at about 3220 rpm. I then started two
> Python processes which were running at 100% CPU time on both cores.
> 
> The CPU temperature slowly raised to 67 degrees (I killed the processes
> at 67, so maybe it would have continued to raise), but the changes of
> the fan speed were hardly noticeable. Maximum speed was at ~3290 rpm.

Core2 can withstand a lot more than that, I don't know exactly how much, but
don't expect Lenovo's EC to be very fan-happy, it won't raise the speed
unless the CPUs are burning hot.

> Could this be a bug in the embedded controller? Somehow this behaviour

Yes, if it is a bug anywhere (and not by design), the bug is in the EC.

> seems a little bit strange: In most cases the speed of the fan is way to
> high, it runs at 3800-4200 rpm even if a lower speed would be
> sufficient. In other cases the fan starts at only 3200 rpm and keeps
> running at this speed, even if the temperature is rising to high values.

Create a log of the fan speed, AND of *all* the thermal readings you get
from both ACPI and ibm-acpi.  Also log the state of the battery (charging,
idle, discharging).  At least the X4x used to change fan profiles depending
on what it was doing to the battery.

The EC looks at a lot more than just the CPU temperature to set the fan
speed :(

> Could anyone with a X61(s) post the /proc/acpi/ibm/fan and
> /proc/acpi/ibm/thermal values when running at "level auto"?

That will vary a lot.  Make a proper log like I described above, starting
from cold machine, cold boot.  Then work for about one hour normally, then
start a CPU hog, or a GPU hog, etc.   That should make it a lot easier to
try to pinpoint the reason for the fan behaviour.

If it IS a bug, I can report it to Lenovo, but ONLY if I get a damn good
backing report describing the bug very, very properly.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh