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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

    Would it be possible to explain why this relation between request and
    the media controller ? Why couldn't request be created from video
    devices ?

    >
    > 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
    >
    > 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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