[PATCH v2 2/6] videodev2.h: add V4L2_DEC_CMD_FLUSH

Jernej Skrabec
2019-09-29T20:01:44Z

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Add this new V4L2_DEC_CMD_FLUSH decoder command and document it.

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[Adjusted description]
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst | 10 +++++++++-
Documentation/media/videodev2.h.rst.exceptions | 1 +
include/uapi/linux/videodev2.h | 1 +
3 files changed, 11 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..f1a504836f31 100644
--- a/Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst
+++ b/Documentation/media/uapi/v4l/vidioc-decoder-cmd.rst
@@ -208,7 +208,15 @@ 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.
+ 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 capture buffer containing the last decoded frame.
+ So this command can be used to explicitly flush that final decoded
+ frame. This command does nothing if there are no held capture buffers.

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)
--
2.23.0