drm: clarify adjusted_mode documentation for bridges

This patch clarifies the adjusted_mode documentation
for bridges.

Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180409152427.12449-1-philippe.cornu@st.com
This commit is contained in:
Philippe Cornu 2018-04-09 17:24:27 +02:00
parent aefff49156
commit 584a0146ec
2 changed files with 23 additions and 4 deletions

View File

@ -178,6 +178,22 @@ struct drm_bridge_funcs {
* then this would be &drm_encoder_helper_funcs.mode_set. The display
* pipe (i.e. clocks and timing signals) is off when this function is
* called.
*
* The adjusted_mode parameter is the mode output by the CRTC for the
* first bridge in the chain. It can be different from the mode
* parameter that contains the desired mode for the connector at the end
* of the bridges chain, for instance when the first bridge in the chain
* performs scaling. The adjusted mode is mostly useful for the first
* bridge in the chain and is likely irrelevant for the other bridges.
*
* For atomic drivers the adjusted_mode is the mode stored in
* &drm_crtc_state.adjusted_mode.
*
* NOTE:
*
* If a need arises to store and access modes adjusted for other
* locations than the connection between the CRTC and the first bridge,
* the DRM framework will have to be extended with DRM bridge states.
*/
void (*mode_set)(struct drm_bridge *bridge,
struct drm_display_mode *mode,

View File

@ -134,10 +134,13 @@ struct drm_crtc_state {
*
* 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.
* is actually programmed into the hardware.
*
* For drivers using drm_bridge, this stores hardware display timings
* used between the CRTC and the first bridge. For other drivers, the
* meaning of the adjusted_mode field is purely driver implementation
* defined information, and will usually be used to store the hardware
* display timings used between the CRTC and encoder blocks.
*/
struct drm_display_mode adjusted_mode;