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diff --git a/Documentation/driver-api/media/maintainer-entry-profile.rst b/Documentation/driver-api/media/maintainer-entry-profile.rst new file mode 100644 index 000000000..ffc712a5f --- /dev/null +++ b/Documentation/driver-api/media/maintainer-entry-profile.rst @@ -0,0 +1,206 @@ +Media Subsystem Profile +======================= + +Overview +-------- + +The media subsystem covers support for a variety of devices: stream +capture, analog and digital TV streams, cameras, remote controllers, HDMI CEC +and media pipeline control. + +It covers, mainly, the contents of those directories: + + - drivers/media + - drivers/staging/media + - Documentation/admin-guide/media + - Documentation/driver-api/media + - Documentation/userspace-api/media + - Documentation/devicetree/bindings/media/\ [1]_ + - include/media + +.. [1] Device tree bindings are maintained by the + OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS maintainers + (see the MAINTAINERS file). So, changes there must be reviewed + by them before being merged via the media subsystem's development + tree. + +Both media userspace and Kernel APIs are documented and the documentation +must be kept in sync with the API changes. It means that all patches that +add new features to the subsystem must also bring changes to the +corresponding API files. + +Due to the size and wide scope of the media subsystem, media's +maintainership model is to have sub-maintainers that have a broad +knowledge of a specific aspect of the subsystem. It is the sub-maintainers' +task to review the patches, providing feedback to users if the patches are +following the subsystem rules and are properly using the media kernel and +userspace APIs. + +Patches for the media subsystem must be sent to the media mailing list +at linux-media@vger.kernel.org as plain text only e-mail. Emails with +HTML will be automatically rejected by the mail server. It could be wise +to also copy the sub-maintainer(s). + +Media's workflow is heavily based on Patchwork, meaning that, once a patch +is submitted, the e-mail will first be accepted by the mailing list +server, and, after a while, it should appear at: + + - https://patchwork.linuxtv.org/project/linux-media/list/ + +If it doesn't automatically appear there after a few minutes, then +probably something went wrong on your submission. Please check if the +email is in plain text\ [2]_ only and if your emailer is not mangling +whitespaces before complaining or submitting them again. + +You can check if the mailing list server accepted your patch, by looking at: + + - https://lore.kernel.org/linux-media/ + +.. [2] If your email contains HTML, the mailing list server will simply + drop it, without any further notice. + + +Media maintainers ++++++++++++++++++ + +At the media subsystem, we have a group of senior developers that +are responsible for doing the code reviews at the drivers (also known as +sub-maintainers), and another senior developer responsible for the +subsystem as a whole. For core changes, whenever possible, multiple +media maintainers do the review. + +The media maintainers that work on specific areas of the subsystem are: + +- Remote Controllers (infrared): + Sean Young <sean@mess.org> + +- HDMI CEC: + Hans Verkuil <hverkuil@xs4all.nl> + +- Media controller drivers: + Laurent Pinchart <laurent.pinchart@ideasonboard.com> + +- ISP, v4l2-async, v4l2-fwnode, v4l2-flash-led-class and Sensor drivers: + Sakari Ailus <sakari.ailus@linux.intel.com> + +- V4L2 drivers and core V4L2 frameworks: + Hans Verkuil <hverkuil@xs4all.nl> + +The subsystem maintainer is: + Mauro Carvalho Chehab <mchehab@kernel.org> + +Media maintainers may delegate a patch to other media maintainers as needed. +On such case, checkpatch's ``delegate`` field indicates who's currently +responsible for reviewing a patch. + +Submit Checklist Addendum +------------------------- + +Patches that change the Open Firmware/Device Tree bindings must be +reviewed by the Device Tree maintainers. So, DT maintainers should be +Cc:ed when those are submitted via devicetree@vger.kernel.org mailing +list. + +There is a set of compliance tools at https://git.linuxtv.org/v4l-utils.git/ +that should be used in order to check if the drivers are properly +implementing the media APIs: + +==================== ======================================================= +Type Tool +==================== ======================================================= +V4L2 drivers\ [3]_ ``v4l2-compliance`` +V4L2 virtual drivers ``contrib/test/test-media`` +CEC drivers ``cec-compliance`` +==================== ======================================================= + +.. [3] The ``v4l2-compliance`` also covers the media controller usage inside + V4L2 drivers. + +Other compilance tools are under development to check other parts of the +subsystem. + +Those tests need to pass before the patches go upstream. + +Also, please notice that we build the Kernel with:: + + make CF=-D__CHECK_ENDIAN__ CONFIG_DEBUG_SECTION_MISMATCH=y C=1 W=1 CHECK=check_script + +Where the check script is:: + + #!/bin/bash + /devel/smatch/smatch -p=kernel $@ >&2 + /devel/sparse/sparse $@ >&2 + +Be sure to not introduce new warnings on your patches without a +very good reason. + +Style Cleanup Patches ++++++++++++++++++++++ + +Style cleanups are welcome when they come together with other changes +at the files where the style changes will affect. + +We may accept pure standalone style cleanups, but they should ideally +be one patch for the whole subsystem (if the cleanup is low volume), +or at least be grouped per directory. So, for example, if you're doing a +big cleanup change set at drivers under drivers/media, please send a single +patch for all drivers under drivers/media/pci, another one for +drivers/media/usb and so on. + +Coding Style Addendum ++++++++++++++++++++++ + +Media development uses ``checkpatch.pl`` on strict mode to verify the code +style, e.g.:: + + $ ./scripts/checkpatch.pl --strict --max-line-length=80 + +In principle, patches should follow the coding style rules, but exceptions +are allowed if there are good reasons. On such case, maintainers and reviewers +may question about the rationale for not addressing the ``checkpatch.pl``. + +Please notice that the goal here is to improve code readability. On +a few cases, ``checkpatch.pl`` may actually point to something that would +look worse. So, you should use good sense. + +Note that addressing one ``checkpatch.pl`` issue (of any kind) alone may lead +to having longer lines than 80 characters per line. While this is not +strictly prohibited, efforts should be made towards staying within 80 +characters per line. This could include using re-factoring code that leads +to less indentation, shorter variable or function names and last but not +least, simply wrapping the lines. + +In particular, we accept lines with more than 80 columns: + + - on strings, as they shouldn't be broken due to line length limits; + - when a function or variable name need to have a big identifier name, + which keeps hard to honor the 80 columns limit; + - on arithmetic expressions, when breaking lines makes them harder to + read; + - when they avoid a line to end with an open parenthesis or an open + bracket. + +Key Cycle Dates +--------------- + +New submissions can be sent at any time, but if they intend to hit the +next merge window they should be sent before -rc5, and ideally stabilized +in the linux-media branch by -rc6. + +Review Cadence +-------------- + +Provided that your patch is at https://patchwork.linuxtv.org, it should +be sooner or later handled, so you don't need to re-submit a patch. + +Except for bug fixes, we don't usually add new patches to the development +tree between -rc6 and the next -rc1. + +Please notice that the media subsystem is a high traffic one, so it +could take a while for us to be able to review your patches. Feel free +to ping if you don't get a feedback in a couple of weeks or to ask +other developers to publicly add Reviewed-by and, more importantly, +``Tested-by:`` tags. + +Please note that we expect a detailed description for ``Tested-by:``, +identifying what boards were used at the test and what it was tested. |