[PATCH 3/6] Documentation/gpu: Document pipe split visual confirmation
From: Rodrigo Siqueira <hidden>
Date: 2021-11-25 15:41:40
Also in:
amd-gfx, dri-devel
Subsystem:
documentation, drm drivers, drm drivers and misc gpu patches, the rest · Maintainers:
Jonathan Corbet, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds
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. Signed-off-by: Rodrigo Siqueira <redacted> --- .../gpu/amdgpu-dc/amdgpu-dc-debug.rst | 28 +++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/Documentation/gpu/amdgpu-dc/amdgpu-dc-debug.rst b/Documentation/gpu/amdgpu-dc/amdgpu-dc-debug.rst
index 532cbbd64863..6dbd21f7f59e 100644
--- a/Documentation/gpu/amdgpu-dc/amdgpu-dc-debug.rst
+++ b/Documentation/gpu/amdgpu-dc/amdgpu-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.
--
2.25.1