diff options
Diffstat (limited to 'include')
| -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; |