Am 14.11.2011 20:20, schrieb Michael Tandy:
I did some more experiments with this webcam, and with a nasty hack
got it working.
Basically the problem seems to be the frame interval requested. If I
replace line 175 of uvc_v4l2.c [1] with
probe->dwFrameInterval = 2500000;
the camera works fine in mjpeg mode.
The frame interval behaves oddly in this camera, in that if you set
the frame interval above a certain threshold the camera seems to
ignore it and send frames at whatever rate it feels like, but if you
set it below a certain threshold the camera exhibits the bug I've
described above, sending back corrupted frames and error codes. Most
likely a firmware bug, as I can't imagine anyone would design a camera
to function that way.
I assume we wouldn't be inclined to patch the kernel to deal with this
one camera's weird behaviour?
[1]
http://lxr.free-electrons.com/source/drivers/media/video/uvc/uvc_v4l2.c?v=2.6.28#L175
Hi Laurent,
i still think that checking the reason of error bit, make sense.
In this case we check the reason of error bit. If we get permanent
buffer underrun or overrun, we should switch to different framerate. Or
notify user to do that.
And probably add the "error bit handler" to the uvc status list on your
page :)
Regards,
Alexey.
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