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. Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx> --- Documentation/gpu/amdgpu/display/dc-debug.rst | 34 ++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) 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 -- 2.25.1
