Re: [PATCH] Subject: [PATCH] x86, AMD: K8 Rev.A-E processors are subject to erratum 400

[Boris Ostrovsky <boris.ostrovsky@amd.com>]

On 04/29/2011 03:55 PM, Ingo Molnar wrote:
>
> * Boris Ostrovsky<ostr@amd64.org>  wrote:
>
>> Signed-off-by: Boris Ostrovsky<Boris.Ostrovsky@amd.com>
>> Acked-by: Borislav Petkov<borislav.petkov@amd.com>
>> Reported-by: Joerg-Volker Peetz<jvpeetz@web.de>
>> Tested-by: Joerg-Volker Peetz<jvpeetz@web.de>
>>
>> Older AMD K8 processors (Revisions A-E) are affected by erratum 400 (APIC
>> timer interrupts don't occur in C states greater than C1). This, for example,
>> means that X86_FEATURE_ARAT flag should not be set for these parts.
>>
>> This addresses regression introduced by commit
>> b87cf80af3ba4b4c008b4face3c68d604e1715c6 (x86, AMD: Set ARAT feature on AMD
>> processors") so it is somewhat high priority.
>
> Hm, what is the regression, how do users see it? Hangs? Delays? Crashes?
> Something more benign? The changelog should really contain such information.


The system becomes unresponsive until an external interrupt (e.g. 
keyboard input) happens. The most obvious effect is that time is not 
reported correctly. We haven't seen anything worse but that's probably 
bad enough.

Do you want me to resubmit the patch with updated comments?

Thanks.
-boris