[PATCH v5 0/3] Enumerate all pixels formats

[Benjamin Gaignard]

The goal of this series is to help userspace applications, like Gstreamer
or Chromium, to categorize decoders and so avoid trying to use decoder
that can't do the require task because it won't support the needed pixel
format.
As example, in today implementation we need to simulate 10 bit header
control to know if the driver support 10 bits pixel formats. With this
new flag it will simpler for userspace applications know if driver
support 10 bit pixel formats and if it is supported by userspace.

An example of how it can be used in GStreamer to discover the
supported pixels formats for stateless decoders is available here:
https://gitlab.freedesktop.org/benjamin.gaignard1/gstreamer/-/commits/v4l2codecs_enum_all_supported_formats?ref_type=heads

v4l2-compliance test of this flag:
https://gitlab.collabora.com/benjamin.gaignard/v4l-utils/-/tree/enum_all_formats?ref_type=heads

changes in version 5:
- Reset the proposal to follow Hans's advices
- Add new flag to be used with index field.
- Make vicodec and visl test driver use the new flag
- Doing the same for Verisilicon driver.

changes in version 4:
- Explicitly document that the new flags are targeting mem2mem devices.

changes in version 3:
- Add a flag to inform userspace application that driver
  as take care of the flag.

changes in version 2:
- Clarify documentation.
- Only keep V4L2_FMT_FLAG_ALL_FORMATS flag in ioctl.

Benjamin

Benjamin Gaignard (3):
  media: videodev2: Add flag to unconditionnaly enumerate pixels formats
  media: test-drivers: Use V4L2_FMT_FLAG_ENUM_ALL flag
  media: verisilicon: Use V4L2_FMT_FLAG_ENUM_ALL flag

 .../userspace-api/media/v4l/vidioc-enum-fmt.rst | 12 +++++++++++-
 .../media/videodev2.h.rst.exceptions            |  1 +
 .../media/platform/verisilicon/hantro_v4l2.c    | 17 ++++++++++++-----
 .../media/test-drivers/vicodec/vicodec-core.c   |  7 ++++---
 drivers/media/test-drivers/visl/visl-video.c    | 11 +++++++----
 include/uapi/linux/videodev2.h                  |  3 +++
 6 files changed, 38 insertions(+), 13 deletions(-)

-- 
2.43.0