linux-kernel - RE: Possible CPU_IDLE bug [WAS: Re: Timer unstability on when using C2 and deeper sleep states (Dell Latitude XT)]

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Date:	Thu, 14 Aug 2008 13:40:14 +0200
From:	Milan Plzik <milan.plzik@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>,
	Venkatesh <venkatesh.pallipadi@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: Possible CPU_IDLE bug [WAS: Re: Timer unstability on when
	using C2 and deeper sleep states (Dell Latitude XT)]

On Št, 2008-08-14 at 11:00 +0200, Thomas Gleixner wrote:
> On Thu, 14 Aug 2008, Milan Plzik wrote:
> >   I tried it just now, is performs a bit better than 2.6.26 (e.g. I
> > don't get that "press any key unless nothing happens" states), even
> > reports a bit more reasonable values of wakeups, but the system
> > sometimes becomes rather slow (e.g. when playing video). I was not able
> > to compile fglrx driver, so I had to change it to radeon one. And also,
> > the number of wakeups reported is not very convincing, though, it
> > changes from 300 to 600 (which is ~ two times the sum of wakeups)
> > without any reason, and sometimes goes even higher.
> > 
> >   I tried to use nolapic_timer option, but it didn't help.
> 
> Can you please try "hpet=disable" on the kernel command line ?

  Looks like this has helped; after cold reboot hpet=disable seems to
help the system to run properly (on 2.6.26 kernel). I wonder what could
cause these problems. In the meanwhile I learned that this machine
doesn't do proper cleanup during reboot -- it seems that state before
reboot affects the state after reboot, so I should probably do some
re-testing with cold reboot after each attempt. I guess I tried
hpet=disable some time ago and after quick reboot it did not work
properly.

> 
> Thanks,
> 	tglx

  Thank you,
	Milan

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