Re: PROBLEM: CPU fan shuts down on load of fan.ko in kernel 2.6.18 and later

[Bjorn Helgaas <bjorn.helgaas@hp.com>]

On Sunday 07 January 2007 13:10, Matthew Brett wrote:
> I am sorry, I am a bit lost.  Should I expect replacing:
> 
> > +       device->flags.force_power_state = 1;
> > +       acpi_bus_set_power(device->handle, state);
> > +       device->flags.force_power_state = 0;
> 
> with:
> 
> > +       if (state == ACPI_STATE_D0)
> > +               acpi_bus_set_power(fan->handle, ACPI_STATE_D3);
> > +       else if (state == ACPI_STATE_D3)
> > +               acpi_bus_set_power(fan->handle, ACPI_STATE_D0);
> > +       acpi_bus_set_power(fan->handle, state);
> 
> in fan.c from 2.6.20-rc3 should solve the problem (replacing
> fan->handle with device->handle)?  It does not seem to.

I think the "acpi_bus_set_power" call was added after
2.6.17.  So if you remove it, I suspect your fan might work
like it used to.

I doubt that's the correct fix, though, because that call
was probably added for a reason.  Konstantin can probably
speak to that.

If you feel like experimenting, you could print out what
state the BIOS tells you the fan is in (from the
acpi_bus_get_power() call), try setting it to either
ACPI_STATE_D0 or ACPI_STATE_D3, and see what the fan does.