[Intel-gfx] [PATCH] drm/i915: Set the map-and-fenceable flag for preallocated objects

[Chris Wilson]

On Wed, Aug 26, 2015 at 03:06:59PM +0200, Daniel Vetter wrote:
> On Wed, Aug 26, 2015 at 12:55:57PM +0100, Chris Wilson wrote:
> > As we mark the preallocated objects as bound, we should also flag them
> > correctly as being map-and-fenceable (if appropriate!) so that latter
> > users do not get confused and try and rebind the pinned vma in order to
> > get a map-and-fenceable binding.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: "Goel, Akash" <akash.goel at intel.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
> > Cc: stable at vger.kernel.org
> 
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> Jani, can you please pick up both? And some bugzilla references for either
> would be great too - Chris?

There's a few candidate "overwrite of address 0" bugs, but no way to
really tell if that is the fbcon or userspace without trial and error.
 
> Oh and does patch 1 fix the execlist resume troubles? Execlist having
> bigger contexts might be enough explanations for the apparent regression.

Hmm, plausible.
 
> And can we igt patch 1 somehow? E.g. with memory pressure plus doing an
> mmap on the legacy fbdev ...

Look at i915_gem_framebuffer for the fbcon gtt address before/after
aperture thrashing. Would also need to switch to a user framebuffer to
drop the scanout pinning.

Or just assert that it is still pinned following a modeset away from
fbcon.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre