Hi,
I know Sakari have posted a series '[RFC 00/19] Async sub-notifiers and
how to use them' which address similar problems as this series. This is
not intended to compete whit his work and Sakari includes one of my v3
patches in his series. Never the less I post this updated series since
it fixes some issues in my v3 implementation and contains some other
fixes for the v4l2-async framework which are not addressed in Sakaris
patches. I think the correct solution to the problems we both try to fix
is a mix of our two series, would you agree Sakari?
This series enables incremental async find and bind of subdevices,
please se patch 4/4 for a more detailed description. This is a rewrite
of the feature since v3, see changelog in this cover letter for the
differences to v3. The two primary reasons for a new implementation
where:
1. Hans expressed an interest having the async complete() callbacks to
happen only once all notifiers in the pipeline where complete. To do
this a stronger connection between the notifiers where needed, hence
the subnotifier is now embedded in struct v4l2_subdev.
Whit this change it is possible to check all notifiers in a pipeline
is complete before calling any of them.
2. There where concerns that the v3 solution was a bit to complex and
hard to refactor in the future if other issues in the v4l2-async
framework where to be addressed. By hiding the notifier in the struct
v4l2_subdev and adding a new function to set that structure the
interface towards drivers are minimized while everything else happens
in the v4l2-async framework. This leaves the interface in a good
position for possible changes in v4l2-async.
This is tested on Renesas H3 and M3-W together with the Renesas CSI-2
and VIN Gen3 driver (posted separately). It is based on top of the media-tree.
* Changes since v4
- Add patch which aborts v4l2_async_notifier_unregister() if the memory
allocation for the device cache fails instead of trying to do as much
as possible but still leave the system in a semi good state.
- Rename v4l2_async_subdev_register_notifier() to
v4l2_async_subdev_notifier_register().
- Add more error checks in v4l2_async_subdev_notifier_register().
- Fix code style issues pointed out by Hans.
- Fix spelling mistakes pointed out by Hans.
* Changes since v3
- Almost a complete rewrite, so drop all Ack-ed by tags.
- Do not add new functions to register/unregister subnotifiers from
callbacks. Instead have have the subdevice drivers populate the
subnotifer list at probe time and have the v4l2-async framework handle
the (un)registration of the notifiers.
- Synchronize the call off the complete() callbacks. They will now all
happens once all notifiers in a pipeline are all complete and from the
edge towards the root device.
- Add a new function v4l2_async_subdev_register_notifier() to hide the
setup of the subnotifier internals to ease improvements later.
* Changes since v2
- Fixed lots of spelling mistakes, thanks Hans!
- Used a goto instead if state variable when restarting iteration over
subdev list as suggested by Sakari. Thank you it's much easier read
now.
- Added Acked-by from Sakari and Hans, thanks!
- Rebased to latest media-tree.
* Changes since v1:
- Added a pre-patch which adds an error check which was previously in
the new incremental async code but is more useful on its own.
- Added documentation to Documentation/media/kapi/v4l2-subdev.rst.
- Fixed data type of bool variable.
- Added call to lockdep_assert_held(), thanks Sakari.
- Fixed commit messages typo, thanks Sakari.
Niklas Söderlund (4):
v4l: async: fix unbind error in v4l2_async_notifier_unregister()
v4l: async: abort if memory allocation fails when unregistering
notifiers
v4l: async: do not hold list_lock when re-probing devices
v4l: async: add subnotifier to subdevices
Documentation/media/kapi/v4l2-subdev.rst | 12 +++
drivers/media/v4l2-core/v4l2-async.c | 170 ++++++++++++++++++++++++-------
include/media/v4l2-async.h | 25 +++++
include/media/v4l2-subdev.h | 5 +
4 files changed, 178 insertions(+), 34 deletions(-)
--
2.13.1
