From c9e42b72b44acc67ede9726e6434b12ba153d901 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 28 Mar 2017 17:53:48 +0200 Subject: drm: Document kms locking a bit better The rules are getting real hard, better to dump my brain into text a bit. This is by far not complete, but I think I reasonable start at least. Some of the older kms structures would need a full doc review anyway ... Cc: Harry Wentland Reviewed-by: Harry Wentland Reviewed-by: Alex Deucher Cc: Maarten Lankhorst Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20170328155349.5972-2-daniel.vetter@ffwll.ch --- include/drm/drm_plane.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'include/drm/drm_plane.h') diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h index 31da9f0c4ad2..7aedbf34f3a6 100644 --- a/include/drm/drm_plane.h +++ b/include/drm/drm_plane.h @@ -456,7 +456,6 @@ enum drm_plane_type { * @funcs: helper functions * @properties: property tracking for this plane * @type: type of plane (overlay, primary, cursor) - * @state: current atomic state for this plane * @zpos_property: zpos property for this plane * @rotation_property: rotation property for this plane * @helper_private: mid-layer private data @@ -473,6 +472,8 @@ struct drm_plane { * Protects modeset plane state, together with the &drm_crtc.mutex of * CRTC this plane is linked to (when active, getting activated or * getting disabled). + * + * For atomic drivers specifically this protects @state. */ struct drm_modeset_lock mutex; @@ -502,6 +503,19 @@ struct drm_plane { const struct drm_plane_helper_funcs *helper_private; + /** + * @state: + * + * Current atomic state for this plane. + * + * This is protected by @mutex. Note that nonblocking atomic commits + * access the current plane state without taking locks. Either by going + * through the &struct drm_atomic_state pointers, see + * for_each_plane_in_state(), for_each_oldnew_plane_in_state(), + * for_each_old_plane_in_state() and for_each_new_plane_in_state(). Or + * through careful ordering of atomic commit operations as implemented + * in the atomic helpers, see &struct drm_crtc_commit. + */ struct drm_plane_state *state; struct drm_property *zpos_property; -- cgit v1.2.3-58-ga151