From: Andi Kleen <andi@firstfloor.org>
To: =?utf-8?Q?St=C3=A9phane?= Marchesin <marcheu@chromium.org>
Cc: linux-kernel@vger.kernel.org, keithp@keithp.com,
        torvalds@linux-foundation.org, seanpaul@chromium.org,
        olofj@chromium.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] mm: Work around Intel SNB GTT bug with some physical pages.
References: <1336432421-17972-1-git-send-email-marcheu@chromium.org>
Date: Mon, 07 May 2012 16:57:09 -0700
In-Reply-To: <1336432421-17972-1-git-send-email-marcheu@chromium.org>
	(=?utf-8?Q?=22St=C3=A9phane?= Marchesin"'s message of "Mon, 7 May 2012
 16:13:41 -0700")
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Stéphane Marchesin <marcheu@chromium.org> writes:

> While investing some Sandy Bridge rendering corruption, I found out
> that all physical memory pages below 1MiB were returning garbage when
> read through the GTT. This has been causing graphics corruption (when
> it's used for textures, render targets and pixmaps) and GPU hangups
> (when it's used for GPU batch buffers).

It would be possible to exlude GFP_DMA from the page allocator. That
covers the first 16MB. You just need a custom zone list with ZONE_DMA.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only
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