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From: Detlev Casanova <detlev.casanova@collabora.com>
To: linux-kernel@vger.kernel.org
Cc: linux-media@vger.kernel.org,
	Daniel Almeida <daniel.almeida@collabora.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Hans Verkuil <hverkuil@xs4all.nl>,
	Detlev Casanova <detlev.casanova@collabora.com>
Subject: [PATCH v4 3/4] doc: visl: Document tpg_verbose parameter
Date: Fri, 15 Dec 2023 11:42:57 -0500
Message-ID: <20231215164447.743787-4-detlev.casanova@collabora.com>
In-Reply-To: <20231215164447.743787-1-detlev.casanova@collabora.com>
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Also document stable frames and what it means for testing tools.

Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 Documentation/admin-guide/media/visl.rst | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/media/visl.rst b/Documentation/admin-guide/media/visl.rst
index db1ef29438e1..cd45145cde68 100644
--- a/Documentation/admin-guide/media/visl.rst
+++ b/Documentation/admin-guide/media/visl.rst
@@ -49,6 +49,10 @@ Module parameters
   visl_dprintk_frame_start, visl_dprintk_nframes, but controls the dumping of
   buffer data through debugfs instead.
 
+- tpg_verbose: Write extra information on each output frame to ease debugging
+  the API. When set to true, the output frames are not stable for a given input
+  as some information like pointers or queue status will be added to them.
+
 What is the default use case for this driver?
 ---------------------------------------------
 
@@ -57,8 +61,12 @@ This assumes that a working client is run against visl and that the ftrace and
 OUTPUT buffer data is subsequently used to debug a work-in-progress
 implementation.
 
-Information on reference frames, their timestamps, the status of the OUTPUT and
-CAPTURE queues and more can be read directly from the CAPTURE buffers.
+Even though no video decoding is actually done, the output frames can be used
+against a reference for a given input, except if tpg_verbose is set to true.
+
+Depending on the tpg_verbose parameter value, information on reference frames,
+their timestamps, the status of the OUTPUT and CAPTURE queues and more can be
+read directly from the CAPTURE buffers.
 
 Supported codecs
 ----------------
-- 
2.41.0