Hi Laurent,
> V4l: device has no mmap support
> ioctl VIDIOCSWIN: Input/output error
> ioctl VIDIOCGWIN: Invalid argument
> ioctl VIDIOCGCHAN: Invalid argument
> ioctl VIDIOCGWIN: Invalid argument
> yuvgrab, read failed!
> yuvgrab, read failed!
> yuvgrab, read failed!
Those ioctls are from the V4L1 API, which the Linux UVC driver doesn't
support. It might be possible to use the V4L1 compatibility layer, and
that's
probably what you're doing already (maybe without even being aware) if
Marratech works on a 32 bits machine. In that case, there might be some
issues with the V4L1 compatibility layer on 64 bit architectures.
That is exactly what I am suspecting...
uvccapture and luvcview:
>
> [EMAIL PROTECTED]:/tmp$ ./uvccapture
> sending ioctl VIDIOC_QUERYCAP
> sending ioctl VIDIOC_S_FMT
> Unable to set format: 22.
> Init v4L2 failed !! exit fatal
Those are definitely V4L2 calls. -22 means invalid argument. There might
again
be some issue with 64 bit architectures, either in the driver or in
luvcview.
I can't help you much as I have no 64 bit machine to test this on.
Actually, I am happy to report that the latest kernel patches have resolved
this issue.
I also have a kernel trace with my debug, this is a part of it that shows
> that the driver calls into the l1 compat layer, which seems odd to me
since
> everything from application to kernel is all l2:
compat_ioctl32 is the 32bit/64bit compatibility layer, not the V4L1
compatibility layer.
With new updates to the kernel videodev and compat_ioctl32 layer we can run
UVC cameras very nicely, using applications like luvcview, it works just
great.
However, the problem is that we would like to use conferencing software that
is written to support old v4L1 mechanism, and the rewrite is going
on...slowly :) But the V4L1 compat layer it it was working could be a
solution for the time being. I tracked couple first ioctl's that fail
without proper support/translation in the v4l_compat_ioctl32 - those are
VIDIOCGMBUF and VIDIOCGCHAN. I am not sure if it is feasible/easy to
implement those, the latter one seems to be just a matter of filling out a
structure according to the camera's features, but the memory mapped buffer
looks a bit challenging. Although looking at the way it is implemented in
videodev - it seems possible to do something similar. I would really
appreciate your opinion on this problem.
Thanks and regards,
--Natalie
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