Re: [PATCH V4] IOMMU, AMD Family15h Model10-1Fh erratum 746Workaround

From: Borislav Petkov
Date: Thu Jan 24 2013 - 14:57:32 EST


On Thu, Jan 24, 2013 at 01:17:53PM -0600, suravee.suthikulpanit@xxxxxxx wrote:
> From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
>
> The IOMMU may stop processing page translations due to a perceived lack
> of credits for writing upstream peripheral page service request (PPR)
> or event logs. If the L2B miscellaneous clock gating feature is enabled
> the IOMMU does not properly register credits after the log request has
> completed, leading to a potential system hang.
>
> BIOSes are supposed to disable L2B micellaneous clock gating by setting
> L2_L2B_CK_GATE_CONTROL[CKGateL2BMiscDisable](D0F2xF4_x90[2]) = 1b. This
> patch corrects that for those which do not enable this workaround.
>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

Acked-by: Borislav Petkov <bp@xxxxxxx>

Thanks for the good work.

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
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