[PATCH v2 7/7] drm/todo: Add bridge related todo items
Sam Ravnborg
sam at ravnborg.org
Wed Oct 20 18:19:01 UTC 2021
- deprecated callbacks in drm_bridge_funcs
- move connector creation to display drivers
v2:
- Updated descriptions in todo.rst
Signed-off-by: Sam Ravnborg <sam at ravnborg.org>
Acked-by: Maxime Ripard <maxime at cerno.tech>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel at ffwll.ch>
---
Documentation/gpu/todo.rst | 49 ++++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 60d1d7ee0719..17c03e7c41e5 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -463,6 +463,55 @@ Contact: Thomas Zimmermann <tzimmermann at suse.de>, Christian König, Daniel Vette
Level: Intermediate
+Drop use of deprecated operations in bridge drivers
+--------------------------------------------------
+
+&struct drm_bridge_funcs contains a number of deprecated operations
+which use can be replaced by the atomic variants.
+
+The following is more or less 1:1 replacements whit the arguments
+and names adjusted:
+* pre_enable => atomic_pre_enable
+* enable => atomic_enable
+* disable => atomic_disable
+* post_disable => atomic_post_disable
+
+* mode_set is no longer required and the implementation shall be merged
+ with atomic_enable.
+
+* mode_fixup => atomic_check
+ mode_fixup() was created a long time ago, when we were supposed to have
+ a single bridge at the output of the CRTC. The bridge could then instruct
+ the CRTC to output a different mode than what the display requires.
+ Now that we have support for multiple bridges, it's not as straightforward,
+ and we've so far just pretended to ignore the problem. The .mode_fixup()
+ operation is used and abused, and just telling people to use .atomic_check()
+ will likely make things worse as that operation has access to the full atomic
+ commit and can alter the mode of pretty much anything. We need to define clear
+ semantics for .atomic_check() in bridges.
+
+
+Contact: bridge maintainers, Sam Ravnborg <sam at ravnborg.org>,
+ Laurent Pinchart <laurent.pinchart at ideasonboard.com>
+
+Level: Beginner or intermediate (depending on the driver)
+
+Move connector creation to display drivers
+------------------------------------------
+
+With the introduction of chained bridges the creation of connectors are moved
+to the display drivers. The flag DRM_BRIDGE_ATTACH_NO_CONNECTOR is used to
+signal to the bridge driver that no connector shall be created and that the
+display driver will take care. Display drivers will in most cases be able to
+utilise drm_bridge_connector_init() for all the logic.
+
+Step 1 is to have all bridge drivers supporting DRM_BRIDGE_ATTACH_NO_CONNECTOR.
+Step 2 is to move connector creation to all relevant display drivers, utilizing
+the drm_bridge_connector where possible.
+
+Contact: Sam Ravnborg <sam at ravnborg.org>, bridge and/or driver maintainer(s)
+
+Level: Intermediate or advanced (depending on the driver)
Core refactorings
=================
--
2.30.2
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