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authorDaniel Vetter <daniel.vetter@ffwll.ch>2017-05-15 11:11:35 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2017-05-23 16:36:06 +0200
commit9de5d4a61cc2a99634e3b51bda0f8e2fdd8f4287 (patch)
treeb7bf4043a742961f4e94438ee8a86a9d863f2ae9 /include
parent3eb220a5319169fb44dcfe1944c731424c2bee5f (diff)
downloadlinux-9de5d4a61cc2a99634e3b51bda0f8e2fdd8f4287.tar.bz2
drm/doc: Document adjusted/request modes a bit better
Laurent started a massive discussion on IRC about this. Let's try to document common usage a bit better. v2: Cross-links+typos. Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Jose Abreu <Jose.Abreu@synopsys.com> Reviewed-by: Jose Abreu <joabreu@synopsys.com> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170515091136.26307-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'include')
-rw-r--r--include/drm/drm_bridge.h2
-rw-r--r--include/drm/drm_crtc.h28
-rw-r--r--include/drm/drm_modeset_helper_vtables.h6
3 files changed, 30 insertions, 6 deletions
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index f703bafc2e30..983054f2e86e 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -100,7 +100,7 @@ struct drm_bridge_funcs {
* 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.
+ * match mode. See also &drm_crtc_state.adjusted_mode for more details.
*
* This is the only hook that allows a bridge to reject a modeset. If
* this function passes all other callbacks must succeed for this
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index adf4e91a9399..b6e3713bd7a9 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -90,8 +90,6 @@ struct drm_plane_helper_funcs;
* @plane_mask: bitmask of (1 << drm_plane_index(plane)) of attached planes
* @connector_mask: bitmask of (1 << drm_connector_index(connector)) of attached connectors
* @encoder_mask: bitmask of (1 << drm_encoder_index(encoder)) of attached encoders
- * @adjusted_mode: for use by helpers and drivers to compute adjusted mode timings
- * @mode: current mode timings
* @mode_blob: &drm_property_blob for @mode
* @state: backpointer to global drm_atomic_state
*
@@ -131,9 +129,33 @@ struct drm_crtc_state {
u32 connector_mask;
u32 encoder_mask;
- /* adjusted_mode: for use by helpers and drivers */
+ /**
+ * @adjusted_mode:
+ *
+ * Internal display timings which can be used by the driver to handle
+ * differences between the mode requested by userspace in @mode and what
+ * is actually programmed into the hardware. It is purely driver
+ * implementation defined what exactly this adjusted mode means. Usually
+ * it is used to store the hardware display timings used between the
+ * CRTC and encoder blocks.
+ */
struct drm_display_mode adjusted_mode;
+ /**
+ * @mode:
+ *
+ * Display timings requested by userspace. The driver should try to
+ * match the refresh rate as close as possible (but note that it's
+ * undefined what exactly is close enough, e.g. some of the HDMI modes
+ * only differ in less than 1% of the refresh rate). The active width
+ * and height as observed by userspace for positioning planes must match
+ * exactly.
+ *
+ * For external connectors where the sink isn't fixed (like with a
+ * built-in panel), this mode here should match the physical mode on the
+ * wire to the last details (i.e. including sync polarities and
+ * everything).
+ */
struct drm_display_mode mode;
/* blob property to expose current mode to atomic userspace */
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index 739b832eb304..361240ca738e 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -147,7 +147,8 @@ struct drm_crtc_helper_funcs {
* encoders need to be fed with. Note that this is the inverse semantics
* of the meaning for the &drm_encoder and &drm_bridge_funcs.mode_fixup
* vfunc. If the CRTC cannot support the requested conversion from mode
- * to adjusted_mode it should reject the modeset.
+ * to adjusted_mode it should reject the modeset. See also
+ * &drm_crtc_state.adjusted_mode for more details.
*
* This function is used by both legacy CRTC helpers and atomic helpers.
* With atomic helpers it is optional.
@@ -528,7 +529,8 @@ struct drm_encoder_helper_funcs {
* mode is the display mode that should be fed to the next element in
* the display chain, either the final &drm_connector or a &drm_bridge.
* The parameter adjusted_mode is the input mode the encoder requires. It
- * can be modified by this callback and does not need to match mode.
+ * can be modified by this callback and does not need to match mode. See
+ * also &drm_crtc_state.adjusted_mode for more details.
*
* This function is used by both legacy CRTC helpers and atomic helpers.
* This hook is optional.