[sane-devel] usblp trouble with all-in-one device

[Johannes Meixner]

Hello,

On Dec 15 16:27 Olaf Meeuwissen wrote (shortened):
> Working on support for a new business oriented all-in-one for iscan, I
> have hit a dead end and would appreciate some insights/suggestions.
> 
> When attaching the device, the kernel loads the usblp module and CUPS
> has no trouble finding the printer part.  On the scanner side however,
> the device is (usually) found but I can't get it to scan.

I have no knowledge how the USB mess is supposed to work
but perhaps issue "D)" in
https://bugzilla.novell.com/show_bug.cgi?id=184798
might be about the same problem?


> Considering the target audience for this device, I can't very well say
> "Oh, just rmmod usblp before you scan and insmod usblp again when you
> are done".

As far as I know this is exactly what the USB stuff in the
current kernels requires.


> Similarly, suggesting to compile a CUPS usb backend using
> usb-libusb.c[1] is also not particularly user friendly.

No ;-)
As far as I know the only solution with the current kernels
is that the CUPS usb backend uses libusb out of the box.


> Is there a way to get SANE, CUPS and usblp to play nice _together_?

As far as I know with the current kernels: No.


But perhaps I am totally wrong and the issue is only because
usblp and libusb try to communiucate with the same USB endpoint
(i.e. with the whole all-in-one device) instead of usblp
communicates only with the USB endpointwhitch matches to
the printer interface of the device and libusb communicates
only with the USB endpoint whitch matches to the scanner interface
of the device (as far as I know all Epson all-in-one devices provide
seperated USB interfaces for the printer unit and the scanner unit).
But I don't know if such a kind of seperated communication is
possible at all with the current kernels.


Kind Regards
Johannes Meixner
-- 
SUSE LINUX Products GmbH, Maxfeldstrasse 5      Mail: jsmeix at suse.de
90409 Nuernberg, Germany                    WWW: http://www.suse.de/