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

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Message-ID: <47780657.8020208@richardharman.com>
Date:	Sun, 30 Dec 2007 15:57:59 -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 03:49:21 +0200
> 
> Note that this problem is only related to AMD64 multi-core laptops. As
> far as I can see, devs might not invest much coding effort into this
> and instead say "Go buy an Intel laptop!", as this really is a hardware
> quirk. And if Andi Kleen is correct, this is not just a laptop vendors'
> problem, but AMD itself doesn't offer support for higher C-states.
> 

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?
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