[Intel-gfx] [PATCH v2] drm/i915: Fallback to using unmappable memory for scanout

[Chris Wilson]

On Thu, Mar 19, 2015 at 04:39:06PM +0000, Damien Lespiau wrote:
> On Thu, Mar 19, 2015 at 11:29:40AM +0000, Chris Wilson wrote:
> > The existing ABI says that scanouts are pinned into the mappable region
> > so that legacy clients (e.g. old Xorg or plymouthd) can write directly
> > into the scanout through a GTT mapping. However if the surface does not
> > fit into the mappable region, we are better off just trying to fit it
> > anywhere and hoping for the best. (Any userspace that is cappable of
> > using ginormous scanouts is also likely not to rely on pure GTT
> > updates.) In the future, there may even be a kernel mediated method for
> > the legacy clients.
> > 
> > v2: Skip fence pinning when not mappable.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Satyanantha, Rama Gopal M <rama.gopal.m.satyanantha at intel.com>
> > Cc: Deepak S <deepak.s at linux.intel.com>
> > Cc: Damien Lespiau <damien.lespiau at intel.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > ---
> 
> Hum, isn't that still overlooking that we can't put the framebuffers at
> the end of the GGTT?

Yes. We don't have the interface yet. When we do we can apply the vtd
requirements as well..
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre