From: Andi Kleen <ak@suse.de>
Organization: SUSE Linux Products GmbH, Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg)
To: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Blacklist Dell Optiplex 320 from using the HPET
Date: Sat, 5 May 2007 01:19:17 +0200
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Cc: john stultz <johnstul@us.ibm.com>,
       "Guilherme M. Schroeder" <guilherme@centralinf.com.br>,
       lkml <linux-kernel@vger.kernel.org>,
       Thomas Gleixner <tglx@linutronix.de>
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On Friday 04 May 2007 23:44:08 Andrew Morton wrote:
> On Fri, 04 May 2007 14:29:04 -0700
> john stultz <johnstul@us.ibm.com> wrote:
> 
> > One of the 2.6.21 regressions was Guilherme's problem seeing his box
> > lock up when the system detected an unstable TSC and dropped back to
> > using the HPET.
> > 
> > In digging deeper, we found the HPET is not actually incrementing on
> > this system. And in fact, the reason why this issue just cropped up was
> > because of Thomas's clocksource watchdog code was comparing the TSC to
> > the HPET (which wasn't moving) and thought the TSC was broken.
> > 
> > Anyway, Guliherme checked for a BIOS update and did not find one, so
> > I've added a DMI blacklist against his system so the HPET is not used.
> > 
> > Many thanks to Guilherme for the slow and laborious testing that finally
> > narrowed down this issue.
> > 
> 
> OK, I tagged that for -stable too.

Don't please. It is completely the wrong approach. DMI should be only last resort,
not first.

-Andi
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