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b2568d6834
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>
60 lines
2.4 KiB
ReStructuredText
60 lines
2.4 KiB
ReStructuredText
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Display Core Debug tools
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DC Visual Confirmation
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======================
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Display core provides a feature named visual confirmation, which is a set of
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bars added at the scanout time by the driver to convey some specific
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information. In general, you can enable this debug option by using::
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echo <N> > /sys/kernel/debug/dri/0/amdgpu_dm_visual_confirm
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Where `N` is an integer number for some specific scenarios that the developer
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wants to enable, you will see some of these debug cases in the following
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subsection.
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Multiple Planes Debug
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---------------------
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If you want to enable or debug multiple planes in a specific user-space
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application, you can leverage a debug feature named visual confirm. For
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enabling it, you will need::
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echo 1 > /sys/kernel/debug/dri/0/amdgpu_dm_visual_confirm
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You need to reload your GUI to see the visual confirmation. When the plane
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configuration changes or a full update occurs there will be a colored bar at
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the bottom of each hardware plane being drawn on the screen.
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* The color indicates the format - For example, red is AR24 and green is NV12
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* The height of the bar indicates the index of the plane
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* Pipe split can be observed if there are two bars with a difference in height
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covering the same plane
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Consider the video playback case in which a video is played in a specific
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plane, and the desktop is drawn in another plane. The video plane should
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feature one or two green bars at the bottom of the video depending on pipe
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split configuration.
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* There should **not** be any visual corruption
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* There should **not** be any underflow or screen flashes
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* There should **not** be any black screens
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* There should **not** be any cursor corruption
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* Multiple plane **may** be briefly disabled during window transitions or
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resizing but should come back after the action has finished
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Pipe Split Debug
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----------------
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Sometimes we need to debug if DCN is splitting pipes correctly, and visual
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confirmation is also handy for this case. Similar to the MPO case, you can use
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the below command to enable visual confirmation::
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echo 1 > /sys/kernel/debug/dri/0/amdgpu_dm_visual_confirm
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In this case, if you have a pipe split, you will see one small red bar at the
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bottom of the display covering the entire display width and another bar
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covering the second pipe. In other words, you will see a bit high bar in the
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second pipe.
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