kernel/linux.git/drivers/gpu/drm/drm_bridge.c, branch linux-6.9.y

drm/bridge: Fix improper bridge init order with pre_enable_prev_first

2024-05-30T07:44:41+00:00

[ Upstream commit e18aeeda0b6905c333df5a0566b99f5c84426098 ] For a given bridge pipeline if any bridge sets pre_enable_prev_first flag then the pre_enable for the previous bridge will be called before pre_enable of this bridge and opposite is done for post_disable. These are the potential bridge flags to alter bridge init order in order to satisfy the MIPI DSI host and downstream panel or bridge to function. However the existing pre_enable_prev_first logic with associated bridge ordering has broken for both pre_enable and post_disable calls. [pre_enable] The altered bridge ordering has failed if two consecutive bridges on a given pipeline enables the pre_enable_prev_first flag. Example: - Panel - Bridge 1 - Bridge 2 pre_enable_prev_first - Bridge 3 - Bridge 4 pre_enable_prev_first - Bridge 5 pre_enable_prev_first - Bridge 6 - Encoder In this example, Bridge 4 and Bridge 5 have pre_enable_prev_first. The logic looks for a bridge which enabled pre_enable_prev_first flag on each iteration and assigned the previou bridge to limit pointer if the bridge doesn't enable pre_enable_prev_first flags. If control found Bridge 2 is pre_enable_prev_first then the iteration looks for Bridge 3 and found it is not pre_enable_prev_first and assigns it's previous Bridge 4 to limit pointer and calls pre_enable of Bridge 3 and Bridge 2 and assign iter pointer with limit which is Bridge 4. Here is the actual problem, for the next iteration control look for Bridge 5 instead of Bridge 4 has iter pointer in previous iteration moved to Bridge 4 so this iteration skips the Bridge 4. The iteration found Bridge 6 doesn't pre_enable_prev_first flags so the limit assigned to Encoder. From next iteration Encoder skips as it is the last bridge for reverse order pipeline. So, the resulting pre_enable bridge order would be, - Panel, Bridge 1, Bridge 3, Bridge 2, Bridge 6, Bridge 5. This patch fixes this by assigning limit to next pointer instead of previous bridge since the iteration always looks for bridge that does NOT request prev so assigning next makes sure the last bridge on a given iteration what exactly the limit bridge is. So, the resulting pre_enable bridge order with fix would be, - Panel, Bridge 1, Bridge 3, Bridge 2, Bridge 6, Bridge 5, Bridge 4, Encoder. [post_disable] The altered bridge ordering has failed if two consecutive bridges on a given pipeline enables the pre_enable_prev_first flag. Example: - Panel - Bridge 1 - Bridge 2 pre_enable_prev_first - Bridge 3 - Bridge 4 pre_enable_prev_first - Bridge 5 pre_enable_prev_first - Bridge 6 - Encoder In this example Bridge 5 and Bridge 4 have pre_enable_prev_first. The logic looks for a bridge which enabled pre_enable_prev_first flags on each iteration and assigned the previou bridge to next and next to limit pointer if the bridge does enable pre_enable_prev_first flag. If control starts from Bridge 6 then it found next Bridge 5 is pre_enable_prev_first and immediately the next assigned to previous Bridge 6 and limit assignments to next Bridge 6 and call post_enable of Bridge 6 even though the next consecutive Bridge 5 is enabled with pre_enable_prev_first. This clearly misses the logic to find the state of next conducive bridge as everytime the next and limit assigns previous bridge if given bridge enabled pre_enable_prev_first. So, the resulting post_disable bridge order would be, - Encoder, Bridge 6, Bridge 5, Bridge 4, Bridge 3, Bridge 2, Bridge 1, Panel. This patch fixes this by assigning next with previou bridge only if the bridge doesn't enable pre_enable_prev_first flag and the next further assign it to limit. This way we can find the bridge that NOT requested prev to disable last. So, the resulting pre_enable bridge order with fix would be, - Encoder, Bridge 4, Bridge 5, Bridge 6, Bridge 2, Bridge 3, Bridge 1, Panel. Validated the bridge init ordering by incorporating dummy bridges in the sun6i-mipi-dsi pipeline Fixes: 4fb912e5e190 ("drm/bridge: Introduce pre_enable_prev_first to alter bridge init order") Signed-off-by: Jagan Teki Tested-by: Michael Trimarchi Reviewed-by: Dave Stevenson Signed-off-by: Robert Foss Link: https://patchwork.freedesktop.org/patch/msgid/20230328170752.1102347-1-jagan@amarulasolutions.com Signed-off-by: Sasha Levin

drm/bridge: remove ->get_edid callback

2024-02-09T08:16:20+00:00

There are no more users of the ->get_edid callback left. They've all been converted to ->edid_read. Remove the callback, and the fallback in drm_bridge_edid_read(). Signed-off-by: Jani Nikula Reviewed-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/34407a355ec6848fc44f8c30d245fcbc5687195e.1706038510.git.jani.nikula@intel.com

drm/bridge: remove drm_bridge_get_edid() in favour of drm_bridge_edid_read()

2024-02-08T15:12:33+00:00

All users of drm_bridge_get_edid() have been converted to use drm_bridge_edid_read(). Remove drm_bridge_get_edid(). Signed-off-by: Jani Nikula Reviewed-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/c51d50edddbe8816eaa63e6ccafa9f2354b506ba.1706038510.git.jani.nikula@intel.com

drm/bridge: add ->edid_read hook and drm_bridge_edid_read()

2024-02-08T15:10:33+00:00

Add new struct drm_edid based ->edid_read hook and drm_bridge_edid_read() function to call the hook. v2: Include drm/drm_edid.h Signed-off-by: Jani Nikula Reviewed-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/9d08d22eaffcb9c59a2b677e45d7e61fc689bc2f.1706038510.git.jani.nikula@intel.com

drm/bridge: migrate bridge_chains to per-encoder file

2023-12-04T14:07:29+00:00

Instead of having a single file with all bridge chains, list bridges under a corresponding per-encoder debugfs directory. While we are at it, also slightly improve the formatting of the bridge data: split a single line entry into multiple lines, include the symbol name of the bridge funcs and add the textual representation of the bridge ops. Example of the listing: $ cat /sys/kernel/debug/dri/0/encoder-0/bridges bridge[0]: dsi_mgr_bridge_funcs type: [0] Unknown ops: [0] bridge[1]: lt9611uxc_bridge_funcs type: [11] HDMI-A OF: /soc@0/geniqup@9c0000/i2c@994000/hdmi-bridge@2b:lontium,lt9611uxc ops: [7] detect edid hpd Reviewed-by: Neil Armstrong Reviewed-by: Tomi Valkeinen Signed-off-by: Dmitry Baryshkov Link: https://patchwork.freedesktop.org/patch/msgid/20231203115315.1306124-3-dmitry.baryshkov@linaro.org

drm/debugfs: rework debugfs directory creation v5

2023-09-01T06:51:18+00:00

Instead of the per minor directories only create a single debugfs directory for the whole device directly when the device is initialized. For DRM devices each minor gets a symlink to the per device directory for now until we can be sure that this isn't useful any more in any way. Accel devices create only the per device directory and also drops the mid layer callback to create driver specific files. v2: cleanup accel component as well v3: fix typo when debugfs is disabled v4: call drm_debugfs_dev_fini() during release as well, some kerneldoc typos fixed v5: rebased and one more kerneldoc fix Signed-off-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20230829110115.3442-4-christian.koenig@amd.com Reviewed-by: Andi Shyti

drm/bridge: Add debugfs print for bridge chains

2023-08-02T08:05:01+00:00

DRM bridges are not visible to the userspace and it may not be immediately clear if the chain is somehow constructed incorrectly. I have had two separate instances of a bridge driver failing to do a drm_bridge_attach() call, resulting in the bridge connector not being part of the chain. In some situations this doesn't seem to cause issues, but it will if DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is used. Add a debugfs file to print the bridge chains. For me, on this TI AM62 based platform, I get the following output: encoder[39] bridge[0] type: 0, ops: 0x0 bridge[1] type: 0, ops: 0x0, OF: /bus@f0000/i2c@20000000/dsi@e:toshiba,tc358778 bridge[2] type: 0, ops: 0x3, OF: /bus@f0000/i2c@20010000/hdmi@48:lontium,lt8912b bridge[3] type: 11, ops: 0x7, OF: /hdmi-connector:hdmi-connector Tested-by: Alexander Stein Reviewed-by: Laurent Pinchart Signed-off-by: Tomi Valkeinen Acked-by: Neil Armstrong Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/20230802-drm-bridge-chain-debugfs-v4-1-7e3ae3d137c0@ideasonboard.com

drm/bridge: Document the expected behaviour of DSI host controllers

2022-12-08T08:56:57+00:00

The exact behaviour of DSI host controllers is not specified, therefore define it. Signed-off-by: Dave Stevenson Reviewed-by: Laurent Pinchart Link: https://lore.kernel.org/r/20221205173328.1395350-7-dave.stevenson@raspberrypi.com Signed-off-by: Maxime Ripard

drm/bridge: Introduce pre_enable_prev_first to alter bridge init order

2022-12-08T08:56:57+00:00

DSI sink devices typically want the DSI host powered up and configured before they are powered up. pre_enable is the place this would normally happen, but they are called in reverse order from panel/connector towards the encoder, which is the "wrong" order. Add a new flag pre_enable_prev_first that any bridge can set to swap the order of pre_enable (and post_disable) for that and the immediately previous bridge. Should the immediately previous bridge also set the pre_enable_prev_first flag, the previous bridge to that will be called before either of those which requested pre_enable_prev_first. eg: - Panel - Bridge 1 - Bridge 2 pre_enable_prev_first - Bridge 3 - Bridge 4 pre_enable_prev_first - Bridge 5 pre_enable_prev_first - Bridge 6 - Encoder Would result in pre_enable's being called as Panel, Bridge 1, Bridge 3, Bridge 2, Bridge 6, Bridge 5, Bridge 4, Encoder. Signed-off-by: Dave Stevenson Tested-by: Frieder Schrempf Reviewed-by: Frieder Schrempf Link: https://lore.kernel.org/r/20221205173328.1395350-5-dave.stevenson@raspberrypi.com Signed-off-by: Maxime Ripard

drm/bridge: Drop unused drm_bridge_chain functions

2022-12-08T08:56:57+00:00

The drm_bridge_chain_{pre_enable,enable,disable,post_disable} has no users left and we have atomic variants that should be used. Drop them so they do not gain new users. Adjust a few comments to avoid references to the dropped functions. Signed-off-by: Sam Ravnborg Reviewed-by: Maxime Ripard Reviewed-by: Laurent Pinchart Cc: Laurent Pinchart Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: Andrzej Hajda Cc: Neil Armstrong Cc: Robert Foss Cc: Daniel Vetter Signed-off-by: Dave Stevenson Link: https://lore.kernel.org/r/20221205173328.1395350-4-dave.stevenson@raspberrypi.com Signed-off-by: Maxime Ripard