Re: [PATCH] drm/i915: don't clflush gem objects in stolen memory

[Imre Deak <imre.deak@intel.com>]

On Wed, 2013-02-13 at 20:39 +0000, Chris Wilson wrote:
> On Wed, Feb 13, 2013 at 09:56:05PM +0200, Imre Deak wrote:
> > As explained by Chris Wilson gem objects in stolen memory are always
> > coherent with the GPU so we don't need to ever flush the CPU caches for
> > these.
> > 
> > This fixes a breakage - at least with the compact sg patches applied -
> > during the resume/restore gtt mappings path, when we tried to clflush an
> > FB object in stolen memory, but since stolen objects don't have backing
> > pages we passed an invalid page pointer to drm_clflush_page().
> > 
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> 
> To the best of my knowledge, this is correct:
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
> 
> Though the stolen framework landed in 3.8, tough call as to whether this
> should be in 3.8 as well given the backported clflush fix... I guess we
> are simply too late, so drm-intel-next +
> Cc: stable@vger.kernel.org
> 
> Imre do you mind digging up the sha of both the introduction of stolen
> and the clflush of unbounded upon resume?

Since afaics this problem relates only to _FBs_ in stolen memory the
first one is:

commit 0ffb0ff283cca16f72caf29c44496d83b0c291fb
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Nov 15 11:32:27 2012 +0000

    drm/i915: Allocate fbcon from stolen memory


and the second:

commit a8e93126a6f10d0a14ba8407ec112b1b3a5e2e97
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Dec 8 14:28:54 2010 +0000

    drm/i915/gtt: Clear the cachelines upon resume
    
    Required for my pineview system to not barf after resuming.
    
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>


--Imre