From: Peter Seiderer <ps.report@xxxxxxx>
This v4l2_buffer flag can be used by drivers to mark a capture buffer
as the last generated buffer, for example after a V4L2_DEC_CMD_STOP
command was issued.
The DocBook is updated to mention mem2mem codecs and the mem2mem draining flow
signals in the VIDIOC_DECODER_CMD V4L2_DEC_CMD_STOP and VIDIOC_ENCODER_CMD
V4L2_ENC_CMD_STOP documentation.
Signed-off-by: Peter Seiderer <ps.report@xxxxxxx>
Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
Changes since v3:
- Added DocBook update mentioning V4L2_BUF_FLAG_LAST in the encoder/decoder
stop command documentation.
---
Documentation/DocBook/media/v4l/io.xml | 10 ++++++++++
Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 6 +++++-
Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml | 5 ++++-
include/trace/events/v4l2.h | 3 ++-
include/uapi/linux/videodev2.h | 2 ++
5 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
index 1c17f80..f3b8bc0 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -1129,6 +1129,16 @@ in this buffer has not been created by the CPU but by some DMA-capable unit,
in which case caches have not been used.</entry>
</row>
<row>
+ <entry><constant>V4L2_BUF_FLAG_LAST</constant></entry>
+ <entry>0x00100000</entry>
+ <entry>Last buffer produced by the hardware. mem2mem codec drivers
+set this flag on the capture queue for the last buffer when the
+<link linkend="vidioc-querybuf">VIDIOC_QUERYBUF</link> or
+<link linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl is called. After the
+queue is drained, the <link linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl will
+not block anymore, but return an &EPIPE;.</entry>
+ </row>
+ <row>
<entry><constant>V4L2_BUF_FLAG_TIMESTAMP_MASK</constant></entry>
<entry>0x0000e000</entry>
<entry>Mask for timestamp types below. To test the
diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml
index 9215627..cbb7135 100644
--- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml
@@ -197,7 +197,11 @@ be muted when playing back at a non-standard speed.
this command does nothing. This command has two flags:
if <constant>V4L2_DEC_CMD_STOP_TO_BLACK</constant> is set, then the decoder will
set the picture to black after it stopped decoding. Otherwise the last image will
-repeat. If <constant>V4L2_DEC_CMD_STOP_IMMEDIATELY</constant> is set, then the decoder
+repeat. mem2mem decoders will stop producing new frames altogether. They will send
+a <constant>V4L2_EVENT_EOS</constant> event after the last frame was decoded and
+will set the <constant>V4L2_BUF_FLAG_LAST</constant> buffer flag when there will
+be no new buffers produced to dequeue.
+If <constant>V4L2_DEC_CMD_STOP_IMMEDIATELY</constant> is set, then the decoder
stops immediately (ignoring the <structfield>pts</structfield> value), otherwise it
will keep decoding until timestamp >= pts or until the last of the pending data from
its internal buffers was decoded.
diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml
index 0619ca5..e9cf601 100644
--- a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml
@@ -129,7 +129,10 @@ this command.</entry>
encoding will continue until the end of the current <wordasword>Group
Of Pictures</wordasword>, otherwise encoding will stop immediately.
When the encoder is already stopped, this command does
-nothing.</entry>
+nothing. mem2mem encoders will send a <constant>V4L2_EVENT_EOS</constant> event
+after the last frame was encoded and will set the
+<constant>V4L2_BUF_FLAG_LAST</constant> buffer flag on the capture queue when
+there will be no new buffers produced to dequeue</entry>
</row>
<row>
<entry><constant>V4L2_ENC_CMD_PAUSE</constant></entry>
diff --git a/include/trace/events/v4l2.h b/include/trace/events/v4l2.h
index b9bb1f2..32c33aa 100644
--- a/include/trace/events/v4l2.h
+++ b/include/trace/events/v4l2.h
@@ -58,7 +58,8 @@
{ V4L2_BUF_FLAG_TIMESTAMP_MASK, "TIMESTAMP_MASK" }, \
{ V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN, "TIMESTAMP_UNKNOWN" }, \
{ V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC, "TIMESTAMP_MONOTONIC" }, \
- { V4L2_BUF_FLAG_TIMESTAMP_COPY, "TIMESTAMP_COPY" })
+ { V4L2_BUF_FLAG_TIMESTAMP_COPY, "TIMESTAMP_COPY" }, \
+ { V4L2_BUF_FLAG_LAST, "LAST" })
#define show_timecode_flags(flags) \
__print_flags(flags, "|", \
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index fbdc360..c642c10 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -809,6 +809,8 @@ struct v4l2_buffer {
#define V4L2_BUF_FLAG_TSTAMP_SRC_MASK 0x00070000
#define V4L2_BUF_FLAG_TSTAMP_SRC_EOF 0x00000000
#define V4L2_BUF_FLAG_TSTAMP_SRC_SOE 0x00010000
+/* mem2mem encoder/decoder */
+#define V4L2_BUF_FLAG_LAST 0x00100000
/**
* struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor
--
2.1.4
--
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