[Intel-gfx] [PATCH 1/3] drm/i915: Added a new 'I915_CPU_MAP_NOT_NEEDED' flag to gem_create ioctl.

[Chris Wilson]

On Fri, Mar 07, 2014 at 03:29:25PM +0530, sourab.gupta at intel.com wrote:
> From: Sourab Gupta <sourab.gupta at intel.com>
> 
> Adding the flag 'I915_CPU_MAP_NOT_NEEDED' to gem_create ioctl.
> This is to indicate the driver that direct cpu access to this
> buffer object is not needed and hence Driver can opt to use Stolen
> area as a backing store for it. When this flag is set, try to
> allocate the objects from Stolen area. Fallback to shmem in case
> of allocation failure.

Besides the issue of
http://blog.ffwll.ch/2013/11/botching-up-ioctls.html, this has an
information leak that we are not clearing the stolen pages. Danny got
extremely fussy over that when I sent this code almost 9 months ago.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre