linux-kernel - Re: Linux 2.6.38.4 : regression due to x86 AMD ARAT feature

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Message-ID: <20110424182041.GA19984@liondog.tnic>
Date:	Sun, 24 Apr 2011 20:20:41 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Jörg-Volker Peetz <jvpeetz@....de>
Cc:	linux-kernel@...r.kernel.org,
	Boris Ostrovsky <boris.ostrovsky@....com>,
	Andreas Herrmann <andreas.herrmann3@....com>,
	Borislav Petkov <borislav.petkov@....com>
Subject: Re: Linux 2.6.38.4 : regression due to x86 AMD ARAT feature

On Sun, Apr 24, 2011 at 10:06:36AM +0200, Jörg-Volker Peetz wrote:
> With 2.6.38.4 the clock slows down and the affected laptop sometimes, e.g. for
> the output of "ps axuw" to appear, needs an input from the keyboard or the
> touchpad. Please find attached the kernel config file and the output of dmesg.
> 
> Commenting out the the lines
> 
> 	if (c->x86 >= 0xf && !cpu_has_amd_erratum(amd_erratum_400))
> 		set_cpu_cap(c, X86_FEATURE_ARAT);
> 
> in arch/x86/kernel/cpu/amd.c makes this laptop work as before with kernel
> 2.6.38.3. I think these lines came with commit
> d7b7f0c401303dd7eafcff11752fe74d3b75c766.

Hmm, interesting.

Can you send also /proc/cpuinfo please?

Looks like your CPU is a single core K8 revE or something but we'd need
the exact family info.

Thanks.

-- 
Regards/Gruss,
    Boris.
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