From b2ea711d2c21ec021de4ff09a0a2b5b4224f9749 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Fri, 11 Oct 2019 06:32:42 -0300
Subject: [PATCH] media: videodev2.h: add V4L2_DEC_CMD_FLUSH

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>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
 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(-)

--- 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, howev
 	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
 ============
--- a/Documentation/media/videodev2.h.rst.exceptions
+++ b/Documentation/media/videodev2.h.rst.exceptions
@@ -434,6 +434,7 @@ replace define V4L2_DEC_CMD_START decode
 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
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -1989,6 +1989,7 @@ 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)
