drm/simple-helpers: Always add planes to the state update

Our update function is hooked to the single plane, which might not get
called for crtc-only updates. Which is surprising, so fix this by
always adding the plane.

While at it document how&when the event should be sent out better in
the kerneldoc.

Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: andrea.merello@gmail.com
Tested-and-Reported-by: andrea.merello@gmail.com
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1471933540-31131-1-git-send-email-daniel.vetter@ffwll.ch

1 files changed, 6 insertions, 0 deletions

diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index 269039722f91..826946ca2b82 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -60,6 +60,12 @@ struct drm_simple_display_pipe_funcs {
 	 *
 	 * This function is called when the underlying plane state is updated.
 	 * This hook is optional.
+	 *
+	 * This is the function drivers should submit the
+	 * &drm_pending_vblank_event from. Using either
+	 * drm_crtc_arm_vblank_event(), when the driver supports vblank
+	 * interrupt handling, or drm_crtc_send_vblank_event() directly in case
+	 * the hardware lacks vblank support entirely.
 	 */
 	void (*update)(struct drm_simple_display_pipe *pipe,
 		       struct drm_plane_state *plane_state);