[PATCH] drm/atomic: pass old crtc state to atomic_begin/flush.

[Maarten Lankhorst]

Op 15-06-15 om 09:10 schreef Daniel Vetter:
> On Fri, Jun 12, 2015 at 11:18:22AM +0200, Maarten Lankhorst wrote:
>> In intel it's useful to keep track of some state changes with old
>> crtc state vs new state, for example to disable initial planes or
>> when a modeset's prevented during fastboot.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Hm, thus far the approach has been that the various ->check callbacks diff
> the state and set appropriate stuff like needs_modeset or planes_changed.
> And with intel_crtc->atomic we've kinda started to build up similar
> things for i915. What do you plan to use this for?
> -Daniel
On a modeset I want to disable all old planes by calling plane->disable_plane, which is old_crtc_state->plane_mask.
This is for initial hw readout, where a plane might be active without a fb set. I want to run it during vblank evasion if possible, which
means in atomic_begin or flush.

commit_plane is not called if the old and new state both have a NULL fb, so the initial plane would stay active in this case.

~Maarten