[PATCH 1/2] drm/fb_cma_helper: Add drm_fb_cma_setup_fence() helper

[Daniel Vetter]

On Thu, Sep 29, 2016 at 11:44 PM, Marek Vasut <marex at denx.de> wrote:
> I have the following right now, I think that's more descriptive as this
> function is not preparing the FB in any way.
>
> /**
>  * drm_fb_cma_extract_and_attach_fence() - Extract fence from plane and
> attach to planestate
>  * @plane: Which plane
>  * @state: Plane state attach fence to
>  *
>  * If the plane fb has an dma-buf attached, fish out the exclusive
>  * fence and attach it to plane state for the atomic helper to wait
>  * on.
>  */

That choice of color is ok with me too, but then you need to have a
pile of text to explain where it should be used (i.e. directly as the
prepare_fb hook). And it is a bit inconsistent with all the other
helpers that can be put into hooks directly. Also,
extract_and_attach_fence _is_ officially part of what a driver should
do in their ->prepare_fb hook. Hence I'm still leaning towards that
(and it's shorter!). And with cma there's nothing else to do (dma
memory is always pinned, which is the other thing prepare_fb should
do), so really it's not even a lie: Your function fully prapares a cma
fb for display as expected by th atomic helpers.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch