[PATCH 2/4] drm/doc: document interactions between PAGE_FLIP_EVENT and atomic

[Simon Ser]

Explain which CRTCs get an event, and uAPI requirements.

Signed-off-by: Simon Ser <contact at emersion.fr>
Cc: Pekka Paalanen <pekka.paalanen at collabora.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 include/uapi/drm/drm_mode.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 92d96a2b6763..c32b171c0ba7 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -946,6 +946,10 @@ struct hdr_output_metadata {
  * Request that the kernel sends back a vblank event (see
  * struct drm_event_vblank) with the &DRM_EVENT_FLIP_COMPLETE type when the
  * page-flip is done.
+ *
+ * When used with the atomic uAPI, vblank events will be sent for every CRTC
+ * included in the commit. At least one CRTC must be included, and all included
+ * CRTCs must be turned on.
  */
 #define DRM_MODE_PAGE_FLIP_EVENT 0x01
 /**
-- 
2.41.0