diff options
| author | Sergey Senozhatsky <senozhatsky@chromium.org> | 2021-09-09 14:24:29 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2021-09-30 11:07:57 +0300 |
| commit | c0acf9cfeee061f041fab778dbdcb34b6ca5e2e7 (patch) | |
| tree | e30af680eb9ce6bfaa6bdae802905f7ab5ffe963 /Documentation/userspace-api | |
| parent | b00a9e59c539684d9e105feafaeee36df11ee493 (diff) | |
| download | linux-c0acf9cfeee061f041fab778dbdcb34b6ca5e2e7.tar.xz | |
media: videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag
This patch lets user-space request a non-coherent 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 byte of a 4 byte ->reserved[1] member of struct
v4l2_requestbuffers. The struct, thus, now has reserved 3 bytes.
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, 13 insertions, 5 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst index f98f18c9e91c..a048a9f6b7b6 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst @@ -113,7 +113,12 @@ than the number requested. ``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 e59306aba2b0..099fa6695167 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst @@ -104,10 +104,13 @@ 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. - * - __u32 - - ``reserved``\ [1] - - A place holder for future extensions. Drivers and applications - must set the array to zero. + * - __u8 + - ``flags`` + - Specifies additional buffer management attributes. + See :ref:`memory-flags`. + * - __u8 + - ``reserved``\ [3] + - Reserved for future extensions. .. _v4l2-buf-capabilities: .. _V4L2-BUF-CAP-SUPPORTS-MMAP: |