Commit b2568d68 authored by Rodrigo Siqueira's avatar Rodrigo Siqueira Committed by Alex Deucher
Browse files

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: default avatarYann Dirson <ydirson@free.fr>
Reviewed-by: default avatarHarry Wentland <harry.wentland@amd.com>
Signed-off-by: default avatarRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 7971fb35

Documentation/gpu/amdgpu/display/dc-debug.rst

+26 −2
Original line number Diff line number Diff line
@@ -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.