Hi!
> Document the request API for V4L2 devices, and amend the documentation
> of system calls influenced by it.
>
> Signed-off-by: Alexandre Courbot <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Cc documentation people?
> +Synopsis
> +========
> +
> +.. c:function:: int ioctl( int request_fd, MEDIA_REQUEST_IOC_QUEUE )
> + :name: MEDIA_REQUEST_IOC_QUEUE
> +
> +
> +Arguments
> +=========
> +
> +``request_fd``
> + File descriptor returned by :ref:`MEDIA_IOC_REQUEST_ALLOC`.
> +
> +
> +Description
> +===========
> +
> +If the media device supports :ref:`requests <media-request-api>`, then
> +this request ioctl can be used to queue a previously allocated request.
> +
> +If the request was successfully queued, then the file descriptor can be
> +:ref:`polled <request-func-poll>` to wait for the request to complete.
> +
> +If the request was already queued before, then ``EBUSY`` is returned.
I'd expect -1 to be returned and errno set to EBUSY?
> +============
> +
> +On success 0 is returned, on error -1 and the ``errno`` variable is set
> +appropriately. The generic error codes are described at the
> +:ref:`Generic Error Codes <gen-errors>` chapter.
> +
> +EBUSY
> + The request was already queued.
> +EPERM
> + The application queued the first buffer directly, but later attempted
> + to use a request. It is not permitted to mix the two APIs.
> +ENOENT
> + The request did not contain any buffers. All requests are required
> + to have at least one buffer. This can also be returned if required
> + controls are missing.
> +ENOMEM
> + Out of memory when allocating internal data structures for this
> + request.
> +EINVAL
> + The request has invalid data.
> +EIO
> + The hardware is in a bad state. To recover, the application needs to
> + stop streaming to reset the hardware state and then try to restart
> + streaming.
Pavel
