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| author | Ezequiel Garcia <ezequiel@collabora.com> | 2019-12-05 15:24:40 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2019-12-16 10:24:55 +0100 |
| commit | 0fb36893c6c129d48965332a23fa4ea6b075ad0c (patch) | |
| tree | b3f05b02e985c7a4274d2a2e4f7c3f7f26924655 /Documentation/media | |
| parent | 961f97ab1ef3e2dbe43fac4913372f58ca4a5f74 (diff) | |
media: vidioc-enum-fmt.rst: clarify format preference
It has been decided to use the ENUM_FMT index value
as a hint for driver preference. This is defined purposedly
in a very liberal way, letting drivers define what "preference"
means.
For instance, the Hantro VPU driver indicates additional
processing to output a given format, and thus implicates
more CPU usage, which is enumerated after native (non-processed)
formats.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Diffstat (limited to 'Documentation/media')
| -rw-r--r-- | Documentation/media/uapi/v4l/vidioc-enum-fmt.rst | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst index 399ef1062bac..8ca6ab701e4a 100644 --- a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst +++ b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst @@ -44,7 +44,9 @@ To enumerate image formats applications initialize the ``type`` and the :ref:`VIDIOC_ENUM_FMT` ioctl with a pointer to this structure. Drivers fill the rest of the structure or return an ``EINVAL`` error code. All formats are enumerable by beginning at index zero and incrementing by -one until ``EINVAL`` is returned. +one until ``EINVAL`` is returned. If applicable, drivers shall return +formats in preference order, where preferred formats are returned before +(that is, with lower ``index`` value) less-preferred formats. .. note:: |