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

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Message-ID: <4DB3DA0C.1050003@web.de>
Date:	Sun, 24 Apr 2011 10:06:36 +0200
From:	Jörg-Volker Peetz <jvpeetz@....de>
To:	linux-kernel@...r.kernel.org
Cc:	Boris Ostrovsky <boris.ostrovsky@....com>
Subject: Re: Linux 2.6.38.4 : regression due to x86 AMD ARAT feature

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.

Do I have to use a kernel parameter to remedy the clock misbehavior?

-- 
Best regards,
Jörg-Volker.

View attachment "config-2.6.38.4" of type "text/plain" (56028 bytes)

View attachment "dmesg-2.6.38.4" of type "text/plain" (27901 bytes)