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, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
index bada17166512..447631018426 100644
--- a/drivers/gpu/drm/drm_simple_kms_helper.c
+++ b/drivers/gpu/drm/drm_simple_kms_helper.c
@@ -34,6 +34,12 @@ static const struct drm_encoder_funcs drm_simple_kms_encoder_funcs = {
         .destroy = drm_encoder_cleanup,
 };
 
+static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
+                                     struct drm_crtc_state *state)
+{
+        return drm_atomic_add_affected_planes(state->state, crtc);
+}
+
 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc)
 {
         struct drm_simple_display_pipe *pipe;
@@ -57,6 +63,7 @@ static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc)
 }
 
 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
+        .atomic_check = drm_simple_kms_crtc_check,
         .disable = drm_simple_kms_crtc_disable,
         .enable = drm_simple_kms_crtc_enable,
 };