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authorRodrigo Siqueira <Rodrigo.Siqueira@amd.com>2021-11-25 10:38:27 -0500
committerAlex Deucher <alexander.deucher@amd.com>2021-12-13 16:33:16 -0500
commitb2568d6834ea5b05f14bf48ec22a474c291b30f2 (patch)
tree92aeccabdfa8c4c527e3639f909b7a7061536852 /Documentation/gpu
parent7971fb3502bbd6b1b88f185879f98f9cc82958df (diff)
downloadlinux-b2568d6834ea5b05f14bf48ec22a474c291b30f2.tar.bz2
Documentation/gpu: Document pipe split visual confirmation
Display core provides a feature that makes it easy for users to debug Pipe Split. This commit introduces how to use such a debug option. 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')
-rw-r--r--Documentation/gpu/amdgpu/display/dc-debug.rst28
1 files changed, 26 insertions, 2 deletions
diff --git a/Documentation/gpu/amdgpu/display/dc-debug.rst b/Documentation/gpu/amdgpu/display/dc-debug.rst
index 532cbbd64863..6dbd21f7f59e 100644
--- a/Documentation/gpu/amdgpu/display/dc-debug.rst
+++ b/Documentation/gpu/amdgpu/display/dc-debug.rst
@@ -2,8 +2,18 @@
Display Core Debug tools
========================
-DC Debugfs
-==========
+DC Visual Confirmation
+======================
+
+Display core provides a feature named visual confirmation, which is a set of
+bars added at the scanout time by the driver to convey some specific
+information. In general, you can enable this debug option by using::
+
+ echo <N> > /sys/kernel/debug/dri/0/amdgpu_dm_visual_confirm
+
+Where `N` is an integer number for some specific scenarios that the developer
+wants to enable, you will see some of these debug cases in the following
+subsection.
Multiple Planes Debug
---------------------
@@ -34,3 +44,17 @@ split configuration.
* 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
+
+Pipe Split Debug
+----------------
+
+Sometimes we need to debug if DCN is splitting pipes correctly, and visual
+confirmation is also handy for this case. Similar to the MPO case, you can use
+the below command to enable visual confirmation::
+
+ echo 1 > /sys/kernel/debug/dri/0/amdgpu_dm_visual_confirm
+
+In this case, if you have a pipe split, you will see one small red bar at the
+bottom of the display covering the entire display width and another bar
+covering the second pipe. In other words, you will see a bit high bar in the
+second pipe.