Re: [PATCH] drm/i915: Do not access stolen memory directly by the CPU, even for error capture

Daniel Vetter
2014-07-15T14:14:58Z

On Thu, Apr 24, 2014 at 02:47:48PM -0700, Ben Widawsky wrote:
> On Wed, Feb 12, 2014 at 07:18:40PM +0000, Chris Wilson wrote:
> > For stolen pages, since it is verboten to access them directly on many
> > architectures, we have to read them through the GTT aperture. If they
> > are not accessible through the aperture, then we have to abort.
> >
> > This was complicated by
> >
> > commit 8b6124a633d8095b0c8364f585edff9c59568a96
> > Author: Chris Wilson <chris@chris-wilson.co.uk>
> > Date: Thu Jan 30 14:38:16 2014 +0000
> >
> > drm/i915: Don't access snooped pages through the GTT (even for error capture)
> >
> > and the desire to use stolen memory for ringbuffers, contexts and
> > batches in the future.
>
> I am somewhat unclear as to whether we want to prefer the aperture for
> reading back objects which may be mapped in multiple address spaces.

Is there a polished version of this floating somewhere which I've missed?
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch