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authorRodrigo Siqueira <Rodrigo.Siqueira@amd.com>2021-11-25 18:38:26 +0300
committerAlex Deucher <alexander.deucher@amd.com>2021-12-14 00:33:16 +0300
commit7971fb3502bbd6b1b88f185879f98f9cc82958df (patch)
tree3783b611281ece9560af45ca10a52d83a1c6c25c /Documentation/gpu/amdgpu
parente91f840142eed8705e6682f838da99a97bd7ea25 (diff)
downloadlinux-7971fb3502bbd6b1b88f185879f98f9cc82958df.tar.xz
Documentation/gpu: Document amdgpu_dm_visual_confirm debugfs entry
Display core provides a feature that makes it easy for users to debug Multiple planes by enabling a visual notification at the bottom of each plane. This commit introduces how to use such a feature. Reviewed-by: Yann Dirson <ydirson@free.fr> Reviewed-by: Harry Wentland <harry.wentland@amd.com> Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'Documentation/gpu/amdgpu')
-rw-r--r--Documentation/gpu/amdgpu/display/dc-debug.rst34
1 files changed, 33 insertions, 1 deletions
diff --git a/Documentation/gpu/amdgpu/display/dc-debug.rst b/Documentation/gpu/amdgpu/display/dc-debug.rst
index bbb8c3fc8eee..532cbbd64863 100644
--- a/Documentation/gpu/amdgpu/display/dc-debug.rst
+++ b/Documentation/gpu/amdgpu/display/dc-debug.rst
@@ -1,4 +1,36 @@
+========================
Display Core Debug tools
========================
-TODO
+DC Debugfs
+==========
+
+Multiple Planes Debug
+---------------------
+
+If you want to enable or debug multiple planes in a specific user-space
+application, you can leverage a debug feature named visual confirm. For
+enabling it, you will need::
+
+ echo 1 > /sys/kernel/debug/dri/0/amdgpu_dm_visual_confirm
+
+You need to reload your GUI to see the visual confirmation. When the plane
+configuration changes or a full update occurs there will be a colored bar at
+the bottom of each hardware plane being drawn on the screen.
+
+* The color indicates the format - For example, red is AR24 and green is NV12
+* The height of the bar indicates the index of the plane
+* Pipe split can be observed if there are two bars with a difference in height
+ covering the same plane
+
+Consider the video playback case in which a video is played in a specific
+plane, and the desktop is drawn in another plane. The video plane should
+feature one or two green bars at the bottom of the video depending on pipe
+split configuration.
+
+* There should **not** be any visual corruption
+* There should **not** be any underflow or screen flashes
+* There should **not** be any black screens
+* There should **not** be any cursor corruption
+* Multiple plane **may** be briefly disabled during window transitions or
+ resizing but should come back after the action has finished