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linux-next/include/drm/drm_atomic.h
Daniel Vetter 321ebf04dc 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 <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2014-11-06 21:08:37 +01:00

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2.7 KiB
C

/*
* Copyright (C) 2014 Red Hat
* Copyright (C) 2014 Intel Corp.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors:
* Rob Clark <robdclark@gmail.com>
* Daniel Vetter <daniel.vetter@ffwll.ch>
*/
#ifndef DRM_ATOMIC_H_
#define DRM_ATOMIC_H_
struct drm_atomic_state * __must_check
drm_atomic_state_alloc(struct drm_device *dev);
void drm_atomic_state_clear(struct drm_atomic_state *state);
void drm_atomic_state_free(struct drm_atomic_state *state);
struct drm_crtc_state * __must_check
drm_atomic_get_crtc_state(struct drm_atomic_state *state,
struct drm_crtc *crtc);
struct drm_plane_state * __must_check
drm_atomic_get_plane_state(struct drm_atomic_state *state,
struct drm_plane *plane);
struct drm_connector_state * __must_check
drm_atomic_get_connector_state(struct drm_atomic_state *state,
struct drm_connector *connector);
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);
int __must_check
drm_atomic_add_affected_connectors(struct drm_atomic_state *state,
struct drm_crtc *crtc);
int
drm_atomic_connectors_for_crtc(struct drm_atomic_state *state,
struct drm_crtc *crtc);
void drm_atomic_legacy_backoff(struct drm_atomic_state *state);
int __must_check drm_atomic_check_only(struct drm_atomic_state *state);
int __must_check drm_atomic_commit(struct drm_atomic_state *state);
int __must_check drm_atomic_async_commit(struct drm_atomic_state *state);
#endif /* DRM_ATOMIC_H_ */