[Intel-gfx] [PATCH 1/2] drm/i915: Mark uneven memory banks on gen4 desktop as unknown swizzling

[Chris Wilson]

On Tue, Nov 17, 2015 at 10:40:51AM +0000, Chris Wilson wrote:
> We have varied reports of swizzling corruption on gen4 desktop, and
> confirmation that it is triggered by uneven memory banks. The
> implication is that the swizzling various between the paired channels
> and the remainder of memory on the single channel. As the object then
> has unpredictable swizzling (it will vary depending on exact page
> allocation and may even change during the object's lifetime as the pages
> are replaced), we have to report to userspace that the swizzling is
> unknown.
> 
> Reported-by: Matti Hämäläinen <ccr at tnsp.org>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=90725
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Matti Hämäläinen <ccr at tnsp.org>
> Cc: stable at vger.kernel.org
Tested-by: Matti Hämäläinen <ccr at tnsp.org>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre