diff options
| author | Brian Starkey <brian.starkey@arm.com> | 2016-10-13 10:47:08 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-10-17 08:07:11 +0200 |
| commit | d807ed1c55fb1b2dcfb2bc49385e227f6bee7669 (patch) | |
| tree | d6422d386983b3e6bd1da80b536ba64751ba30c0 /include/drm | |
| parent | f7741aa75e76440f4e9ecfe512feebe9bce33ca8 (diff) | |
| download | linux-d807ed1c55fb1b2dcfb2bc49385e227f6bee7669.tar.bz2 | |
drm: atomic: Clarify documentation around drm_atomic_crtc_needs_modeset
Add some additional comments to more explicitly describe the meaning and
usage of the three CRTC modeset detection booleans: mode_changed,
connectors_changed and active_changed.
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Brian Starkey <brian.starkey@arm.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1476352028-16701-1-git-send-email-brian.starkey@arm.com
Diffstat (limited to 'include/drm')
| -rw-r--r-- | include/drm/drm_atomic.h | 11 | ||||
| -rw-r--r-- | include/drm/drm_crtc.h | 5 |
2 files changed, 15 insertions, 1 deletions
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h index 9701f2dfb784..c52f99415c55 100644 --- a/include/drm/drm_atomic.h +++ b/include/drm/drm_atomic.h @@ -365,8 +365,17 @@ int __must_check drm_atomic_nonblocking_commit(struct drm_atomic_state *state); * * To give drivers flexibility struct &drm_crtc_state has 3 booleans to track * whether the state CRTC changed enough to need a full modeset cycle: - * connectors_changed, mode_changed and active_change. This helper simply + * connectors_changed, mode_changed and active_changed. This helper simply * combines these three to compute the overall need for a modeset for @state. + * + * The atomic helper code sets these booleans, but drivers can and should + * change them appropriately to accurately represent whether a modeset is + * really needed. In general, drivers should avoid full modesets whenever + * possible. + * + * For example if the CRTC mode has changed, and the hardware is able to enact + * the requested mode change without going through a full modeset, the driver + * should clear mode_changed during its ->atomic_check. */ static inline bool drm_atomic_crtc_needs_modeset(struct drm_crtc_state *state) diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 0aa292526567..92246619947c 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -116,6 +116,11 @@ struct drm_plane_helper_funcs; * never return in a failure from the ->atomic_check callback. Userspace assumes * that a DPMS On will always succeed. In other words: @enable controls resource * assignment, @active controls the actual hardware state. + * + * The three booleans active_changed, connectors_changed and mode_changed are + * intended to indicate whether a full modeset is needed, rather than strictly + * describing what has changed in a commit. + * See also: drm_atomic_crtc_needs_modeset() */ struct drm_crtc_state { struct drm_crtc *crtc; |