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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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