From f35f5d72e70e6b91389eb98fcabf43b79f40587f Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 23 Aug 2018 09:56:22 -0400 Subject: media: videodev2.h: add new capabilities for buffer types VIDIOC_REQBUFS and VIDIOC_CREATE_BUFFERS will return capabilities telling userspace what the given buffer type is capable of. Signed-off-by: Hans Verkuil Reviewed-by: Tomasz Figa Acked-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- .../media/uapi/v4l/vidioc-create-bufs.rst | 14 +++++++- Documentation/media/uapi/v4l/vidioc-reqbufs.rst | 42 +++++++++++++++++++++- 2 files changed, 54 insertions(+), 2 deletions(-) (limited to 'Documentation/media/uapi') diff --git a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst index a39e18d69511..eadf6f757fbf 100644 --- a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst +++ b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst @@ -102,7 +102,19 @@ than the number requested. - ``format`` - Filled in by the application, preserved by the driver. * - __u32 - - ``reserved``\ [8] + - ``capabilities`` + - Set by the driver. If 0, then the driver doesn't support + capabilities. In that case all you know is that the driver is + guaranteed to support ``V4L2_MEMORY_MMAP`` and *might* support + other :c:type:`v4l2_memory` types. It will not support any others + capabilities. See :ref:`here ` for a list of the + capabilities. + + If you want to just query the capabilities without making any + other changes, then set ``count`` to 0, ``memory`` to + ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type. + * - __u32 + - ``reserved``\ [7] - A place holder for future extensions. Drivers and applications must set the array to zero. diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst index 316f52c8a310..d4bbbb0c60e8 100644 --- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst +++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst @@ -88,10 +88,50 @@ any DMA in progress, an implicit ``V4L2_MEMORY_DMABUF`` or ``V4L2_MEMORY_USERPTR``. See :c:type:`v4l2_memory`. * - __u32 - - ``reserved``\ [2] + - ``capabilities`` + - Set by the driver. If 0, then the driver doesn't support + capabilities. In that case all you know is that the driver is + guaranteed to support ``V4L2_MEMORY_MMAP`` and *might* support + other :c:type:`v4l2_memory` types. It will not support any others + capabilities. + + If you want to query the capabilities with a minimum of side-effects, + then this can be called with ``count`` set to 0, ``memory`` set to + ``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. +.. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}| + +.. _v4l2-buf-capabilities: +.. _V4L2-BUF-CAP-SUPPORTS-MMAP: +.. _V4L2-BUF-CAP-SUPPORTS-USERPTR: +.. _V4L2-BUF-CAP-SUPPORTS-DMABUF: +.. _V4L2-BUF-CAP-SUPPORTS-REQUESTS: + +.. cssclass:: longtable + +.. flat-table:: V4L2 Buffer Capabilities Flags + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * - ``V4L2_BUF_CAP_SUPPORTS_MMAP`` + - 0x00000001 + - This buffer type supports the ``V4L2_MEMORY_MMAP`` streaming mode. + * - ``V4L2_BUF_CAP_SUPPORTS_USERPTR`` + - 0x00000002 + - This buffer type supports the ``V4L2_MEMORY_USERPTR`` streaming mode. + * - ``V4L2_BUF_CAP_SUPPORTS_DMABUF`` + - 0x00000004 + - This buffer type supports the ``V4L2_MEMORY_DMABUF`` streaming mode. + * - ``V4L2_BUF_CAP_SUPPORTS_REQUESTS`` + - 0x00000008 + - This buffer type supports :ref:`requests `. Return Value ============ -- cgit v1.2.3-59-g8ed1b