Laurent Pinchart
805d4311a5
Due to a historical mishap, the v4l2_subdev_frame_interval structure is the only part of the V4L2 subdev userspace API that doesn't contain a 'which' field. This prevents trying frame intervals using the subdev 'TRY' state mechanism. Adding a 'which' field is simple as the structure has 8 reserved fields. This would however break userspace as the field is currently set to 0, corresponding to V4L2_SUBDEV_FORMAT_TRY, while the corresponding ioctls currently operate on the 'ACTIVE' state. We thus need to add a new subdev client cap, V4L2_SUBDEV_CLIENT_CAP_INTERVAL_USES_WHICH, to indicate that userspace is aware of this new field. All drivers that implement the subdev .get_frame_interval() and .set_frame_interval() operations are updated to return -EINVAL when operating on the TRY state, preserving the current behaviour. While at it, fix a bad copy&paste in the documentation of the struct v4l2_subdev_frame_interval_enum 'which' field. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> # for imx-media Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for tegra-video Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.