From 321ebf04dc7ab5c54d658f93db0ffe35277664ab Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 4 Nov 2014 22:57:27 +0100 Subject: drm/atomic: Refcounting for plane_state->fb So my original plan was that the drm core refcounts framebuffers like with the legacy ioctls. But that doesn't work for a bunch of reasons: - State objects might live longer than until the next fb change happens for a plane. For example delayed cleanup work only happens _after_ the pageflip ioctl has completed. So this definitely doesn't work without the plane state holding its own references. - The other issue is transition from legacy to atomic implementations, where the driver works under a mix of both worlds. Which means legacy paths might not properly update the ->fb pointer under plane->state->fb. Which is a bit a problem when then someone comes around and _does_ try to clean it up when it's long gone. The second issue is just a bit a transition bug, since drivers should update plane->state->fb in all the paths that aren't converted yet. But a bit more robustness for the transition can't hurt - we pull similar tricks with cleaning up the old fb in the transitional helpers already. The pattern for drivers that transition is if (plane->state) drm_atomic_set_fb_for_plane(plane->state, plane->fb); inserted after the fb update has logically completed at the end of ->set_config (or ->set_base/mode_set if using the crtc helpers), ->page_flip, ->update_plane or any other entry point which updates plane->fb. v2: Update kerneldoc - copypasta fail. v3: Fix spelling in the commit message (Sean). Reviewed-by: Sean Paul Signed-off-by: Daniel Vetter --- include/drm/drm_atomic.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h index 5bb15f550c42..9d919168bc11 100644 --- a/include/drm/drm_atomic.h +++ b/include/drm/drm_atomic.h @@ -46,6 +46,8 @@ drm_atomic_get_connector_state(struct drm_atomic_state *state, int __must_check drm_atomic_set_crtc_for_plane(struct drm_plane_state *plane_state, struct drm_crtc *crtc); +void drm_atomic_set_fb_for_plane(struct drm_plane_state *plane_state, + struct drm_framebuffer *fb); int __must_check drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, struct drm_crtc *crtc); -- cgit v1.2.3