diff options
author | Daniel Vetter | 2015-12-04 09:45:47 +0100 |
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committer | Daniel Vetter | 2015-12-08 16:07:53 +0100 |
commit | da024fe58680a46346cfbeba5db705d33f39b313 (patch) | |
tree | 56a22b3ff8d9bbf387f83aef21b0205cce09985d /include/drm | |
parent | 2be94971c759da872efce99fa823ea17cdb7cc8b (diff) |
drm/bridge: Improve kerneldoc
Especially document the assumptions and semantics of the callbacks
carefully. Just a warm-up excercise really.
v2: Spelling fixes (Eric).
v3: Consolidate more with existing docs:
- Remove the overview section explaining the bridge funcs, that's
now all in the drm_bridge_funcs kerneldoc in much more detail.
- Use & to reference structs so that kerneldoc automatically inserts
hyperlinks.
v4: Review from Thierry.
Cc: Eric Anholt <eric@anholt.net>
Cc: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Archit Taneja <architt@codeaurora.org> (v3)
Link: http://patchwork.freedesktop.org/patch/msgid/1449218769-16577-7-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'include/drm')
-rw-r--r-- | include/drm/drm_crtc.h | 102 |
1 files changed, 96 insertions, 6 deletions
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index e8f8e4e9a6a1..7f80fae1a45f 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -883,24 +883,114 @@ struct drm_plane { /** * struct drm_bridge_funcs - drm_bridge control functions * @attach: Called during drm_bridge_attach - * @mode_fixup: Try to fixup (or reject entirely) proposed mode for this bridge - * @disable: Called right before encoder prepare, disables the bridge - * @post_disable: Called right after encoder prepare, for lockstepped disable - * @mode_set: Set this mode to the bridge - * @pre_enable: Called right before encoder commit, for lockstepped commit - * @enable: Called right after encoder commit, enables the bridge */ struct drm_bridge_funcs { int (*attach)(struct drm_bridge *bridge); + + /** + * @mode_fixup: + * + * This callback is used to validate and adjust a mode. The paramater + * mode is the display mode that should be fed to the next element in + * the display chain, either the final &drm_connector or the next + * &drm_bridge. The parameter adjusted_mode is the input mode the bridge + * requires. It can be modified by this callback and does not need to + * match mode. + * + * This is the only hook that allows a bridge to reject a modeset. If + * this function passes all other callbacks must succeed for this + * configuration. + * + * NOTE: + * + * This function is called in the check phase of atomic modesets, which + * can be aborted for any reason (including on userspace's request to + * just check whether a configuration would be possible). Drivers MUST + * NOT touch any persistent state (hardware or software) or data + * structures except the passed in adjusted_mode parameter. + * + * RETURNS: + * + * True if an acceptable configuration is possible, false if the modeset + * operation should be rejected. + */ bool (*mode_fixup)(struct drm_bridge *bridge, const struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode); + /** + * @disable: + * + * This callback should disable the bridge. It is called right before + * the preceding element in the display pipe is disabled. If the + * preceding element is a bridge this means it's called before that + * bridge's ->disable() function. If the preceding element is a + * &drm_encoder it's called right before the encoder's ->disable(), + * ->prepare() or ->dpms() hook from struct &drm_encoder_helper_funcs. + * + * The bridge can assume that the display pipe (i.e. clocks and timing + * signals) feeding it is still running when this callback is called. + */ void (*disable)(struct drm_bridge *bridge); + + /** + * @post_disable: + * + * This callback should disable the bridge. It is called right after + * the preceding element in the display pipe is disabled. If the + * preceding element is a bridge this means it's called after that + * bridge's ->post_disable() function. If the preceding element is a + * &drm_encoder it's called right after the encoder's ->disable(), + * ->prepare() or ->dpms() hook from struct &drm_encoder_helper_funcs. + * + * The bridge must assume that the display pipe (i.e. clocks and timing + * singals) feeding it is no longer running when this callback is + * called. + */ void (*post_disable)(struct drm_bridge *bridge); + + /** + * @mode_set: + * + * This callback should set the given mode on the bridge. It is called + * after the ->mode_set() callback for the preceding element in the + * display pipeline has been called already. The display pipe (i.e. + * clocks and timing signals) is off when this function is called. + */ void (*mode_set)(struct drm_bridge *bridge, struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode); + /** + * @pre_enable: + * + * This callback should enable the bridge. It is called right before + * the preceding element in the display pipe is enabled. If the + * preceding element is a bridge this means it's called before that + * bridge's ->pre_enable() function. If the preceding element is a + * &drm_encoder it's called right before the encoder's ->enable(), + * ->commit() or ->dpms() hook from struct &drm_encoder_helper_funcs. + * + * The display pipe (i.e. clocks and timing signals) feeding this bridge + * will not yet be running when this callback is called. The bridge must + * not enable the display link feeding the next bridge in the chain (if + * there is one) when this callback is called. + */ void (*pre_enable)(struct drm_bridge *bridge); + + /** + * @enable: + * + * This callback should enable the bridge. It is called right after + * the preceding element in the display pipe is enabled. If the + * preceding element is a bridge this means it's called after that + * bridge's ->enable() function. If the preceding element is a + * &drm_encoder it's called right after the encoder's ->enable(), + * ->commit() or ->dpms() hook from struct &drm_encoder_helper_funcs. + * + * The bridge can assume that the display pipe (i.e. clocks and timing + * signals) feeding it is running when this callback is called. This + * callback must enable the display link feeding the next bridge in the + * chain if there is one. + */ void (*enable)(struct drm_bridge *bridge); }; |