linux-kernel - [PATCH 2/8] videodev2.h: add V4L2_DEC_CMD

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Message-Id: <20190822194500.2071-3-jernej.skrabec@siol.net>
Date:   Thu, 22 Aug 2019 21:44:54 +0200
From:   Jernej Skrabec <jernej.skrabec@...l.net>
To:     mchehab@...nel.org, hverkuil-cisco@...all.nl,
        paul.kocialkowski@...tlin.com, mripard@...nel.org
Cc:     pawel@...iak.com, m.szyprowski@...sung.com,
        kyungmin.park@...sung.com, tfiga@...omium.org, wens@...e.org,
        acourbot@...omium.org, gregkh@...uxfoundation.org,
        jernej.skrabec@...l.net, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-arm-kernel@...ts.infradead.org, ezequiel@...labora.com,
        jonas@...boo.se
Subject: [PATCH 2/8] videodev2.h: add V4L2_DEC_CMD_FLUSH

From: Hans Verkuil <hverkuil-cisco@...all.nl>

Add this new V4L2_DEC_CMD_FLUSH decoder command and document it.

Signed-off-by: Hans Verkuil <hverkuil-cisco@...all.nl>
Signed-off-by: Jernej Skrabec <jernej.skrabec@...l.net>
---
 Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst | 11 ++++++++++-
 Documentation/media/videodev2.h.rst.exceptions      |  1 +
 include/uapi/linux/videodev2.h                      |  1 +
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst b/Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst
index 57f0066f4cff..0bffef6058f7 100644
--- a/Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst
+++ b/Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst
@@ -208,7 +208,16 @@ introduced in Linux 3.3. They are, however, mandatory for stateful mem2mem decod
 	been started yet, the driver will return an ``EPERM`` error code. When
 	the decoder is already running, this command does nothing. No
 	flags are defined for this command.
-
+    * - ``V4L2_DEC_CMD_FLUSH``
+      - 4
+      - Flush any held capture buffers. Only valid for stateless decoders,
+        and only if ``V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF`` was set.
+	This command is typically used when the application reached the
+	end of the stream and the last output buffer had the
+	``V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF`` flag set. This would prevent
+	dequeueing the last capture buffer containing the last decoded frame.
+	So this command can be used to explicitly flush that last decoded
+	frame.
 
 Return Value
 ============
diff --git a/Documentation/media/videodev2.h.rst.exceptions b/Documentation/media/videodev2.h.rst.exceptions
index adeb6b7a15cb..a79028e4d929 100644
--- a/Documentation/media/videodev2.h.rst.exceptions
+++ b/Documentation/media/videodev2.h.rst.exceptions
@@ -434,6 +434,7 @@ replace define V4L2_DEC_CMD_START decoder-cmds
 replace define V4L2_DEC_CMD_STOP decoder-cmds
 replace define V4L2_DEC_CMD_PAUSE decoder-cmds
 replace define V4L2_DEC_CMD_RESUME decoder-cmds
+replace define V4L2_DEC_CMD_FLUSH decoder-cmds
 
 replace define V4L2_DEC_CMD_START_MUTE_AUDIO decoder-cmds
 replace define V4L2_DEC_CMD_PAUSE_TO_BLACK decoder-cmds
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 4fa9f543742d..91a79e16089c 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -1978,6 +1978,7 @@ struct v4l2_encoder_cmd {
 #define V4L2_DEC_CMD_STOP        (1)
 #define V4L2_DEC_CMD_PAUSE       (2)
 #define V4L2_DEC_CMD_RESUME      (3)
+#define V4L2_DEC_CMD_FLUSH       (4)
 
 /* Flags for V4L2_DEC_CMD_START */
 #define V4L2_DEC_CMD_START_MUTE_AUDIO	(1 << 0)
-- 
2.22.1