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    Subjectv4l device in userspace
    >>>>> "Salvatore" == Salvatore Sanfilippo <> writes:

    Salvatore> Hello, I'm trying to implement a v4l device driver for
    Salvatore> symbian based smart phones. In theory it is very
    Salvatore> simple:

    Salvatore> I've a little program running in the phone, capturing
    Salvatore> images from the camera and sending it to the linux box
    Salvatore> via bluetooth.

    Salvatore> In the linux box side, I've a deamon capturing this
    Salvatore> images (via a bluetooth SP channel), and.... I've to
    Salvatore> pass the images to a fake v4l device driver that
    Salvatore> actually gets the images form userspace.

    Salvatore> Basically I've to pass by the kernel just for the
    Salvatore> interface, and not to do real kernel-side work (like to
    Salvatore> access to the some kind of hardware).

    Salvatore> So I've some questions ( thanks in advance for any
    Salvatore> reply).

    Salvatore> 1) What's the best way to pass relatively high-band
    Salvatore> data between the v4l fake driver and userspace? A char
    Salvatore> device will do the work? ioctl?

    Salvatore> 2) What about some way to handle ioctl directly from
    Salvatore> userspace? Given this support I may implement the whole
    Salvatore> code in userspace. And I guess there are a lot of
    Salvatore> other real world problems that can be handled in
    Salvatore> userspace given the ability to handle ioctl from there.

    Salvatore> If you think 2) is reasonable I may actually implement
    Salvatore> some simple form of generic char driver that just
    Salvatore> allows userspace programs to handle read/write/ioctl
    Salvatore> opreations, and then use this to fix my real issue.

    Salvatore> Thank you very much for the help, and sorry if there is
    Salvatore> something conceptually wrong in my questions.

    Sounds like you should take a look at the v4l loopback device
    Otherwise it may be better to ask the question on the v4l mailing list

    Anyway, since you already capture the video, why do you have to pipe
    it through a v4l device?


    | Dr. Marcus O.C. Metzler | |
    | | |
    |>>> Quis custodiet ipsos custodes <<<|
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