[PATCH v2] drm: add a drm_atomic_helper_plane_check_update

[Maarten Lankhorst]

Op 13-07-15 om 13:50 schreef John Hunter:
> From: Zhao Junwang <zhjwpku at gmail.com>
>
> This is the equivalent helper to drm_plane_helper_check_update
> for legacy drivers, but using atomic state to check things.
>
> Motivated by the atomic conversion of the bochs driver.
>
> v2: according to Daniel's comment
>     -polish the kerneldoc comment to match the signatures
>     -crtc->mode is legacy state, we need to look at crtc_state
>      instead
>
>     according to Maarten's comment
>     -there is no need for can_update_disabled in the atomic world,
>      so, we can delete that parameter
>
> v3: according to Daniel's comment
>     -this function call can't fail, add a WARN_ON
>     -use drm_atomic_get_existing_crtc_state
>
>     according to Maarten's comment
>     -kill off the plane parameter and rename state to plane_state
>     -do not handling NULL, i.e. no need to check plane_state in
>      atomic.
>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Zhao Junwang <zhjwpku at gmail.com>

Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>