path: root/Documentation
diff options
authorHans Verkuil <hverkuil-cisco@xs4all.nl>2019-10-11 06:32:40 -0300
committerMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-10-21 07:37:57 -0300
commit137272cdf7cc5be835f44216e6003769d1638480 (patch)
treed72ddc241e6533e749de7ed65751d1373b48284c /Documentation
parent4b1d7c2760d26363c497b959a81f8d055ba767c1 (diff)
media: vb2: add V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF
This patch adds support for the V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF flag. It also adds a new V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF capability. Drivers should set vb2_queue->subsystem_flags to VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF to indicate support for this flag. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation')
2 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/buffer.rst b/Documentation/media/uapi/v4l/buffer.rst
index 1cbd9cde57f3..9149b57728e5 100644
--- a/Documentation/media/uapi/v4l/buffer.rst
+++ b/Documentation/media/uapi/v4l/buffer.rst
@@ -607,6 +607,19 @@ Buffer Flags
applications shall use this flag for output buffers if the data in
this buffer has not been created by the CPU but by some
DMA-capable unit, in which case caches have not been used.
+ - 0x00000200
+ - Only valid if ``V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF`` is
+ set. It is typically used with stateless decoders where multiple
+ output buffers each decode to a slice of the decoded frame.
+ Applications can set this flag when queueing the output buffer
+ to prevent the driver from dequeueing the capture buffer after
+ the output buffer has been decoded (i.e. the capture buffer is
+ 'held'). If the timestamp of this output buffer differs from that
+ of the previous output buffer, then that indicates the start of a
+ new frame and the previously held capture buffer is dequeued.
* .. _`V4L2-BUF-FLAG-LAST`:
diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
index d7faef10e39b..d0c643db477a 100644
--- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
+++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
@@ -125,6 +125,7 @@ aborting or finishing any DMA in progress, an implicit
.. cssclass:: longtable
@@ -150,6 +151,11 @@ aborting or finishing any DMA in progress, an implicit
- The kernel allows calling :ref:`VIDIOC_REQBUFS` while buffers are still
mapped or exported via DMABUF. These orphaned buffers will be freed
when they are unmapped or when the exported DMABUF fds are closed.
+ - 0x00000020
+ - Only valid for stateless decoders. If set, then userspace can set the
+ ``V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF`` flag to hold off on returning the
+ capture buffer until the OUTPUT timestamp changes.
Return Value

Privacy Policy