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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/media
parent4b1d7c2760d26363c497b959a81f8d055ba767c1 (diff)
downloadlinux-137272cdf7cc5be835f44216e6003769d1638480.tar.gz
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/media')
-rw-r--r--Documentation/media/uapi/v4l/buffer.rst13
-rw-r--r--Documentation/media/uapi/v4l/vidioc-reqbufs.rst6
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.
+    * .. _`V4L2-BUF-FLAG-M2M-HOLD-CAPTURE-BUF`:
+
+      - ``V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF``
+      - 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`:
 
       - ``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
 .. _V4L2-BUF-CAP-SUPPORTS-DMABUF:
 .. _V4L2-BUF-CAP-SUPPORTS-REQUESTS:
 .. _V4L2-BUF-CAP-SUPPORTS-ORPHANED-BUFS:
+.. _V4L2-BUF-CAP-SUPPORTS-M2M-HOLD-CAPTURE-BUF:
 
 .. 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.
+    * - ``V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF``
+      - 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
 ============