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| author | Sergey Senozhatsky <senozhatsky@chromium.org> | 2020-05-14 18:01:45 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-06-23 13:32:41 +0200 |
| commit | 1e0b2318fa75d186ee0d2be31843ce867385fcc4 (patch) | |
| tree | e44403a8bbe0ebea86a1587a3f113156b2f82c10 /Documentation/userspace-api | |
| parent | 7b4b45555c79db03dad8192e6ef85cb30236827b (diff) | |
| download | linux-1e0b2318fa75d186ee0d2be31843ce867385fcc4.tar.bz2 | |
media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag
This patch lets user-space to request a non-consistent memory
allocation during CREATE_BUFS and REQBUFS ioctl calls.
= CREATE_BUFS
struct v4l2_create_buffers has seven 4-byte reserved areas,
so reserved[0] is renamed to ->flags. The struct, thus, now
has six reserved 4-byte regions.
= CREATE_BUFS32
struct v4l2_create_buffers32 has seven 4-byte reserved areas,
so reserved[0] is renamed to ->flags. The struct, thus, now
has six reserved 4-byte regions.
= REQBUFS
We use one bit of a ->reserved[1] member of struct v4l2_requestbuffers,
which is now renamed to ->flags. Unlike v4l2_create_buffers, struct
v4l2_requestbuffers does not have enough reserved room. Therefore for
backward compatibility ->reserved and ->flags were put into anonymous
union.
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Diffstat (limited to 'Documentation/userspace-api')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst | 7 | ||||
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst | 11 |
2 files changed, 15 insertions, 3 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst index e1afc5b504c2..f2a702870fad 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst @@ -121,7 +121,12 @@ than the number requested. other changes, then set ``count`` to 0, ``memory`` to ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type. * - __u32 - - ``reserved``\ [7] + - ``flags`` + - Specifies additional buffer management attributes. + See :ref:`memory-flags`. + + * - __u32 + - ``reserved``\ [6] - A place holder for future extensions. Drivers and applications must set the array to zero. diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst index 96a59793d857..75d894d9c36c 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst @@ -112,10 +112,17 @@ aborting or finishing any DMA in progress, an implicit ``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will free any previously allocated buffers, so this is typically something that will be done at the start of the application. + * - union { + - (anonymous) + * - __u32 + - ``flags`` + - Specifies additional buffer management attributes. + See :ref:`memory-flags`. * - __u32 - ``reserved``\ [1] - - A place holder for future extensions. Drivers and applications - must set the array to zero. + - Kept for backwards compatibility. Use ``flags`` instead. + * - } + - .. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}| |