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| author | Jacopo Mondi <jacopo@jmondi.org> | 2020-05-07 17:12:49 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-05-12 17:03:26 +0200 |
| commit | 3fb0ee8b3b79ee9c8fb7769bdf802bffeae7e085 (patch) | |
| tree | ed1520460313915b3c985600613d5fee113e1507 /Documentation/userspace-api/media/v4l/vidioc-subdev-g-fmt.rst | |
| parent | 18200e9e243d9095be953cf09cba29f9b3b5f262 (diff) | |
| download | linux-3fb0ee8b3b79ee9c8fb7769bdf802bffeae7e085.tar.bz2 | |
media: Documentation: media: Document read-only subdevice
Document a new kAPI function to register subdev device nodes in read only
mode and for each affected ioctl report how access is restricted.
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.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/media/v4l/vidioc-subdev-g-fmt.rst')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-subdev-g-fmt.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-fmt.rst index 69d60e18664b..909ee9f90867 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-fmt.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-fmt.rst @@ -78,6 +78,11 @@ current links configuration or sub-device controls value. For instance, a low-pass noise filter might crop pixels at the frame boundaries, modifying its output frame size. +If the subdev device node has been registered in read-only mode, calls to +``VIDIOC_SUBDEV_S_FMT`` are only valid if the ``which`` field is set to +``V4L2_SUBDEV_FORMAT_TRY``, otherwise an error is returned and the errno +variable is set to ``-EPERM``. + Drivers must not return an error solely because the requested format doesn't match the device capabilities. They must instead modify the format to match what the hardware can provide. The modified format @@ -146,6 +151,9 @@ EINVAL ``pad`` references a non-existing pad, or the ``which`` field references a non-existing format. +EPERM + The ``VIDIOC_SUBDEV_S_FMT`` ioctl has been called on a read-only subdevice + and the ``which`` field is set to ``V4L2_SUBDEV_FORMAT_ACTIVE``. ============ |