Re: [Intel-gfx] Interrupt latency on some 945GM platforms

From: Paolo Ornati
Date: Sat Sep 25 2010 - 06:28:31 EST


On Tue, 21 Sep 2010 15:56:53 -0700
Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> wrote:

> > I've a laptop with 945GM (Asus x5dij) and with 2.6.32+ kernels I'm
> > having random, but not frequent, screen flickering problems (for some
> > reasons 2.6.31 works fine).
> >
> > Problem goes away with "nohz=off".
> >
> > I'll try with "processor.max_cstate=?" and see if that works too.
>
> Can you guys try something like this? My theory is that 945GM has some
> power management behavior we're failing to configure correctly. If
> disabling it works, then it's likely related.

UPDATE: "processor.max_cstate=2" doesn't solve the sporadic flicker
problem.

The patch, applied on top of 2.6.35.4, freezes the laptop on boot.

Summary:
nohz=off good
processor.max_cstate=1 good
processor.max_cstate=2 bad

Bye,

--
Paolo Ornati
Linux 2.6.35.4 on x86_64
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