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Documentation/gpu: Document pipe split visual confirmation

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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>
This commit is contained in:
Rodrigo Siqueira 2021-11-25 10:38:27 -05:00 committed by Alex Deucher
parent 7971fb3502
commit b2568d6834
1 changed files with 26 additions and 2 deletions
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28
Documentation/gpu/amdgpu/display/dc-debug.rst
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@ -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.