Re: Linux 2.6.38.4 : regression due to x86 AMD ARAT feature

From: Jiri Slaby
Date: Fri Apr 29 2011 - 14:34:52 EST


On 04/24/2011 09:44 PM, Ostrovsky, Boris wrote:
> Borislav Petkov wrote, on 04/24/11 20:20:
>> 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.

> It's an old family fh processor (CPUID 00020F42) that
cpu_has_amd_erratum(amd_erratum_400) apparently hasn't picked up. Since
all fh processors are affected by this erratum I'll replace "c->x86 >=
0xf" with "c->x86 > 0xf" (and probably fix erratum formula anyway).

Hi, what's the status of this please?

I don't see the fix neither in the -next tree.

thanks,
--
js
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