[Bugme-new] [Bug 8850] New: CPU fan always on full speed with VIA VN800

[bugme-daemon at bugzilla.kernel.org]

http://bugzilla.kernel.org/show_bug.cgi?id=8850

           Summary: CPU fan always on full speed with VIA VN800
           Product: ACPI
           Version: 2.5
     KernelVersion: 2.6.22
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Power-Thermal
        AssignedTo: acpi_power-thermal at kernel-bugs.osdl.org
        ReportedBy: nka at users.mns.ru


Distribution: Gentoo Linux

Hardware Environment: RoverBook Partner W500L (re-branded FIC LM7VW) with VIA
C7 1.5GHz CPU, VIA VN800 + VT8237R+. The latest available BIOS version from
manufacturer's site is flashed.

Software Environment: Laptop runs Gentoo Linux x86 with latest available
packages.

Problem Description: the CPU fan is always on and its speed is high. VIA C7 CPU
itsels is very low-temperature device and fan should be very slow most of the
time. I can't control fan's speed via /proc/acpi/fan/FAN/state or
/proc/acpi/fan/thermal_zone/THRM/cooling_mode.

rikz # cat /proc/acpi/fan/FAN/state
status:                  on

rikz # cat /proc/acpi/thermal_zone/THRM/*
0 - Active; 1 - Passive
<polling disabled>
state:                   ok
temperature:             54 C
critical (S5):           110 C
passive:                 78 C: tc1=3 tc2=1 tsp=80 devices=CPU0
active[0]:               60 C: devices= FAN


Even when CPU is 100% busy for a long time, its temperature is lower than 55 C.
When idle it is 43-45 C.
MS Windows slows down the fan when CPU is cool and speeds it up when CPU is
busy.

cat 3 > /proc/acpi/fan/FAN/state does nothing
cat 1 > /proc/acpi/thermal_zone/THRM/cooling_mode does nothing
trip_points are non-writable as I undersrand.

So I just want to lower the speed of the CPU fan, but I see no ways to do it.
The CPU temperature is quiet low and it should be a safe intention.


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