[sane-devel] R: Re: R: Re: R: Re: scanner Epson DX4250 not working in Ubuntu 11.10

Richard Ryniker ryniker at alum.mit.edu
Thu Apr 26 16:01:37 UTC 2012

>Would this explain why the backend works the first time it is called
>from within a shell, and then stops working until a new shell is
>opened (as I described earlier)?

No...  unless the first (successful) operation leaves some data behind
(environment variable?)  that causes the second (failed) operation to act
differently.  Perhaps the device type or other data is remembered, and
the original device identification or initialization process is not
repeated.  This difference could explain why the second operation fails,
but a new shell works.

This is only speculation based on the behavior you report, not knowledge
based on familiarity with the device.

If you perform one scan successfully, then unplug and reconnect the
scanner, will another scan in the same shell work?  If it does work,
maybe there is something left behind in the USB system that explains the
failure.  If the second scan fails after the device is reconnected,
something different in user space is more likely.

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