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SubjectRe: [RFC PATCH 0/9] media: base request API support
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Le vendredi 15 décembre 2017 à 16:56 +0900, Alexandre Courbot a écrit :
> Here is a new attempt at the request API, following the UAPI we agreed on in
> Prague. Hopefully this can be used as the basis to move forward.
>
> This series only introduces the very basics of how requests work: allocate a
> request, queue buffers to it, queue the request itself, wait for it to complete,
> reuse it. It does *not* yet use Hans' work with controls setting. I have
> preferred to submit it this way for now as it allows us to concentrate on the
> basic request/buffer flow, which was harder to get properly than I initially
> thought. I still have a gut feeling that it can be improved, with less back-and-
> forth into drivers.
>
> Plugging in controls support should not be too hard a task (basically just apply
> the saved controls when the request starts), and I am looking at it now.
>
> The resulting vim2m driver can be successfully used with requests, and my tests
> so far have been successful.
>
> There are still some rougher edges:
>
> * locking is currently quite coarse-grained
> * too many #ifdef CONFIG_MEDIA_CONTROLLER in the code, as the request API
> depends on it - I plan to craft the headers so that it becomes unnecessary.
> As it is, some of the code will probably not even compile if
> CONFIG_MEDIA_CONTROLLER is not set
>
> But all in all I think the request flow should be clear and easy to review, and
> the possibility of custom queue and entity support implementations should give
> us the flexibility we need to support more specific use-cases (I expect the
> generic implementations to be sufficient most of the time though).
>
> A very simple test program exercising this API is available here (don't forget
> to adapt the /dev/media0 hardcoding):
> https://gist.github.com/Gnurou/dbc3776ed97ea7d4ce6041ea15eb0438

It looks like the example uses Hans control work you just mention.
Notably, it uses v4l2_ext_controls ctrls.request.

>
> Looking forward to your feedback and comments!
>
> Alexandre Courbot (8):
> media: add request API core and UAPI
> media: request: add generic queue
> media: request: add generic entity ops
> media: vb2: add support for requests
> media: vb2: add support for requests in QBUF ioctl
> media: v4l2-mem2mem: add request support
> media: vim2m: add media device
> media: vim2m: add request support
>
> Hans Verkuil (1):
> videodev2.h: Add request field to v4l2_buffer
>
> drivers/media/Makefile | 4 +-
> drivers/media/media-device.c | 6 +
> drivers/media/media-request-entity-generic.c | 56 ++++
> drivers/media/media-request-queue-generic.c | 150 ++++++++++
> drivers/media/media-request.c | 390 ++++++++++++++++++++++++++
> drivers/media/platform/vim2m.c | 46 +++
> drivers/media/usb/cpia2/cpia2_v4l.c | 2 +-
> drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 7 +-
> drivers/media/v4l2-core/v4l2-ioctl.c | 99 ++++++-
> drivers/media/v4l2-core/v4l2-mem2mem.c | 34 +++
> drivers/media/v4l2-core/videobuf2-core.c | 59 +++-
> drivers/media/v4l2-core/videobuf2-v4l2.c | 32 ++-
> include/media/media-device.h | 3 +
> include/media/media-entity.h | 6 +
> include/media/media-request.h | 282 +++++++++++++++++++
> include/media/v4l2-mem2mem.h | 19 ++
> include/media/videobuf2-core.h | 25 +-
> include/media/videobuf2-v4l2.h | 2 +
> include/uapi/linux/media.h | 11 +
> include/uapi/linux/videodev2.h | 3 +-
> 20 files changed, 1216 insertions(+), 20 deletions(-)
> create mode 100644 drivers/media/media-request-entity-generic.c
> create mode 100644 drivers/media/media-request-queue-generic.c
> create mode 100644 drivers/media/media-request.c
> create mode 100644 include/media/media-request.h
> [unhandled content-type:application/pgp-signature]
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