Re: linux-next: Tree for June 13: IO APIC breakage on HP nx6325

From: Rafael J. Wysocki
Date: Fri Jun 20 2008 - 08:21:15 EST


On Friday, 20 of June 2008, Matthew Garrett wrote:
> On Fri, Jun 20, 2008 at 01:53:58PM +0200, Rafael J. Wysocki wrote:
>
> > What exactly I observe is that in this case:
> > 1) The cooling fan is 100% on, as though the box were overheating, which seems
> > to indicate some serious confusion of the platform (the mechanism turning
> > the fan 100% on is supposed to be transparent to software).
> > 2) Everything seems to slow down substantially, at least as soon as X is
> > started.
>
> What does ACPI claim the trip points are set to in this case? On the
> 6125, if IRQ 2 is enabled in the APIC then the DSDT sets all the thermal
> trip points to 16 degrees C. I suspect this means that enabling IRQ 2 is
> the wrong thing to do on this chipset.

Ah, indeed, thanks for the hint. This is the output of

$ cat /proc/acpi/thermal_zone/TZ*/trip_points

in the failing case:

critical (S5): 105 C
passive: 16 C: tc1=1 tc2=2 tsp=100 devices=C000 C001
active[0]: 16 C: devices=C34F
active[1]: 16 C: devices=C350
active[2]: 16 C: devices=C351
active[3]: 16 C: devices=C352
critical (S5): 100 C
passive: 16 C: tc1=1 tc2=2 tsp=300 devices=C000 C001
critical (S5): 100 C
passive: 16 C: tc1=1 tc2=2 tsp=300 devices=C000 C001

(also available at: http://www.sisk.pl/kernel/debug/20080620/trip-points.txt).

So, the observed slowdown may be a result of throttling.

Thanks,
Rafael
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