# Re: xcam/xscanimage hangs w/ SANE 0.57

David Mosberger-Tang (davidm@azstarnet.com)
Thu, 29 May 1997 16:22:04 -0700

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>>>>> On Thu, 29 May 1997 17:37:53 -0400, Mark Cornick <mcornick@zorak.gsfc.nasa.gov> said:

Mark> I've got a problem that's completely baffled me. A few days
Mark> ago I installed SANE 0.57, which I use with a color QuickCam
Mark> (on /dev/lp1, with the port in ECP mode.) This worked fine
Mark> until today. In xcam, I hit "play", get one image, and then
Mark> xcam hangs (no new images, can't pull down menus or click
Mark> buttons, etc.) A similar thing happens with xscanimage - I can
Mark> scan one preview image, then the program hangs if I try to
Mark> scan another image.

Mark> I've tried undoing everything I've changed in the past day or
Mark> so (different color depths, different window managers, etc.)
Mark> and nothing changes. I've tried running as root, and it does
Mark> the same thing (I have xcam/xscanimage/scanimage installed
Mark> setuid root so I can run them as non-root.) I did upgrade to
Mark> Red Hat 4.2 a few days ago, but all was well yesterday with
Mark> 4.2 running (at least, I think so.) scanimage still grabs
Mark> images just fine, and the QuickCam shows up in a scanimage -L.

Hmmh, I seem to vaguely recall that ECP may cause problems with QCam.
I suppose you could try switching it into regular bidirectional mode,
but I doubt that's the problem given that things used to work for you.

Another potential problem source is /tmp/LOCK.qcam.0x<port-addr>.
It's a lockfile that controls access to the camera. If something goes
wrong, that lock might not be released properly (though I haven't seen
any problems with this in a long time).

Rather than the strace output, it would be more useful to have the
debug output you get with environment variables SANE_DEBUG_QCAM and
SANE_DEBUG_DLL set to 128. That should at least give an idea of where
the camera gets stuck.

--david

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