RE: Regression in intel_idle on Avaton/Rangely Mohon Peak board

From: Brown, Len
Date: Wed Apr 02 2014 - 17:58:54 EST


> [ 0.840668] intel_idle: lapic_timer_reliable_states 0x2
vs.
> [ 0.877528] intel_idle: lapic_timer_reliable_states 0xffffffff

This means CPUID.ARAT is set for the new board, and not set
for the old board. You can observe that also in /proc/cpuinfo flags
where you will likely also find a visible stepping difference between
these two boards.

Bring-up Avoton had ARAT disabled, and also had broken deep C-states.
It looks like that is what your old board has. Throw it away and
use only production steppings. If you are stuck w/ pre-production hardware,
then you need to manually modify upstream Linux to make it happy --
since upstream Linux only cares about production hardware.

thanks,
-Len

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