On 08/10/18 12:46, Pavel Machek wrote: > Hi! >> From: Alexandre Courbot <acourbot@xxxxxxxxxxxx> >> >> Document the request API for V4L2 devices, and amend the documentation >> of system calls influenced by it. >> >> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxxxx> >> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> > >> --- a/Documentation/media/uapi/v4l/buffer.rst >> +++ b/Documentation/media/uapi/v4l/buffer.rst >> @@ -306,10 +306,15 @@ struct v4l2_buffer >> - A place holder for future extensions. Drivers and applications >> must set this to 0. >> * - __u32 >> - - ``reserved`` >> + - ``request_fd`` >> - >> - - A place holder for future extensions. Drivers and applications >> - must set this to 0. >> + - The file descriptor of the request to queue the buffer to. If specified >> + and flag ``V4L2_BUF_FLAG_REQUEST_FD`` is set, then the buffer will be > > Delete "specified and" -- 0 is valid fd? Good catch! > >> + queued to that request. This is set by the user when calling >> + :ref:`ioctl VIDIOC_QBUF <VIDIOC_QBUF>` and ignored by other ioctls. >> + If the device does not support requests, then ``EPERM`` will be returned. >> + If requests are supported but an invalid request FD is given, then >> + ``ENOENT`` will be returned. > > Should this still specify that this should be 0 if > V4L2_BUF_FLAG_REQUEST_FD is not set? I don't think so. But I can mentioned with request_fd that it is ignored if V4L2_BUF_FLAG_REQUEST_FD is not set. Regards, Hans > > Pavel >
