linux-kernel - Re: [PATCH] Option to disable AMD C1E (allows dynticks to work)

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Message-ID: <47779EDA.8070408@richardharman.com>
Date:	Sun, 30 Dec 2007 08:36:26 -0500
From:	Richard Harman <richard@...hardharman.com>
To:	Eduard-Gabriel Munteanu <eduard.munteanu@...ux360.ro>
CC:	pharon@...il.com, Rene Herman <rene.herman@...access.nl>,
	"David P. Reed" <dpreed@...d.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH] Option to disable AMD C1E (allows dynticks to work)



Eduard-Gabriel Munteanu wrote:
> On Sun, 30 Dec 2007 15:57:59 -0500
> Richard Harman <richard@...hardharman.com> wrote:
> 
>> I think I may have a monkey wrench to throw into this, I finally got 
>> around to testing the C1E patch, and the port80 patch.  End result: 
>> port80 patch has zero effect on this laptop, and the C1E patch makes
>> it stable.
>>
>> AMD C1E patch 'force_amd_c1e' (disabling the workaround):
>>
>> hpet0: at MMIO 0xfed00000, IRQs 2, 8, 31
>> hpet0: 3 32-bit timers, 25000000 Hz
>> Time: hpet clocksource has been installed.
>> Clockevents: could not switch to one-shot mode: lapic is not
>> functional. Could not switch to high resolution mode on CPU 0
>> Clockevents: could not switch to one-shot mode: lapic is not
>> functional. Could not switch to high resolution mode on CPU 1
>>
>> And with the C1E workaround enabled, the kernel doesn't whine that
>> the lapic isn't functional.
>>
>> Those were the kernel messages I was trying to paste in my earlier 
>> message, saying that the lapic works.  Do I have a DV6000 laptop that
>> is a strange beast all in itself?
> 
> These two patches are not related in any way, they address two
> different problems. My patch enables dynticks (and those messages don't
> show up anymore), but it doesn't prevent your computer from locking up
> as you said before.
> 

The C1E patch, which permits the lapic to function *does* make my system 
stable.  My previous method of testing (using USB peripherals) and 
checking /proc/interrupts for ERRor interrupts so far hasn't caused the 
system to lock up.

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