[PATCH v2] drm/vgem: Attach sw fences to exported vGEM dma-buf (ioctl)

[Chris Wilson]

On Tue, Jul 12, 2016 at 01:46:21PM +0100, Chris Wilson wrote:
> vGEM buffers are useful for passing data between software clients and
> hardware renders. By allowing the user to create and attach fences to
> the exported vGEM buffers (on the dma-buf), the user can implement a
> deferred renderer and queue hardware operations like flipping and then
> signal the buffer readiness (i.e. this allows the user to schedule
> operations out-of-order, but have them complete in-order).
> 
> This also makes it much easier to write tightly controlled testcases for
> dma-buf fencing and signaling between hardware drivers.
> 
> v2: Don't pretend the fences exist in an ordered timeline, but allocate
> a separate fence-context for each fence so that the fences are
> unordered.
> 
> Testcase: igt/vgem_basic/dmabuf-fence
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Sean Paul <seanpaul at chromium.org>
> Cc: Zach Reizner <zachr at google.com>
> Cc: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Acked-by: Zach Reizner <zachr at google.com>

For purely selfish reasons that this enables more testing for i915,
poke?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre