[Intel-gfx] [PATCH] drm/i915: Declare the swizzling unknown for L-shaped configurations

[Chris Wilson]

On Sun, Jun 28, 2015 at 09:19:26AM +0100, Chris Wilson wrote:
> The old style of memory interleaving swizzled upto the end of the
> first even bank of memory, and then used the remainder as unswizzled on
> the unpaired bank - i.e. swizzling is not constant for all memory. This
> causes problems when we try to migrate memory and so the kernel prevents
> migration at all when we detect L-shaped inconsistent swizzling.
> However, this issue also extends to userspace who try to manually detile
> into memory as the swizzling for an individual page is unknown (it
> depends on its physical address only known to the kernel), userspace
> cannot correctly swizzle.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91105
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: stable at vger.kernel.org

Daniel since you dropped v2 and had already reviewed this version, it
would have been useful had you done the swap...
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre