linux-kernel - Re: [PATCH] pci: Reenable the AMD IOMMU if it's mysteriously vanished over suspend

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Message-ID: <20100930173945.GA16596@srcf.ucam.org>
Date:	Thu, 30 Sep 2010 18:39:45 +0100
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	linux-kernel@...r.kernel.org
Cc:	linux-pci@...r.kernel.org, joerg.roedel@....com,
	jbarnes@...tuousgeek.org
Subject: Re: [PATCH] pci: Reenable the AMD IOMMU if it's mysteriously
	vanished over suspend

On Thu, Sep 30, 2010 at 11:38:28AM -0400, Matthew Garrett wrote:
> AMD's reference BIOS code had a bug that could result in the firmware
> failing to reenable the iommu on resume. It transpires that this causes
> certain less than desirable behaviour when it comes to PCI accesses, to
> whit them ending up somewhere near Bristol when the more desirable outcome
> was Edinburgh. Sadness ensues, perhaps along with filesystem corruption.
> Let's make sure that it gets turned back on.

Of course, this isn't actually sufficient - nothing in the iommu code 
appears to reprogram the BAR, for instance. Joerg, how is this meant to 
work?

-- 
Matthew Garrett | mjg59@...f.ucam.org
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