[cups.bugs] [MOD] STR #2888: USB backend issue with CanonMF4140 printer

[Michael Sweet]

Holger Jahn wrote:
> Hi Michael,
> 
>> This is ultimately a problem with the USB printer module in the kernel 
>> and
>> not an issue with the CUPS backend, since we just look for the devices 
>> the
>> kernel reports and use the one that corresponds to your printer.
> 
> So, do you think the issue is related to the usblp kernel module or some
> other USB kernel module?

It isn't "usblp", but "printer".  Yes, the issue is with the kernel
driver not working with the printer when bidirectional IO is used.

>> CUPS 1.4 has a new libusb-based backend which may work better with this
>> printer - it does *not* use the kernel printer module and thus can avoid
>> the problems associated with it...
> 
> Well, I have learnt that the scanner functionality of this printer works
> just fine with the latest SANE 1.1 drivers from their CVS.

SANE uses libusb as well.

> Is CUPS 1.4 available & usable at the moment?

It is available as developer snapshots on cups.org.  It is not for
production use, but it generally stable enough for personal use.

> Regarding the USB kernel printer module, what do you suggest? I can
> update my current thread there if you want me to.

You'll just have to keep bugging the kernel developers - the current
driver doesn't work well with some devices when bidirectional IO is
used...

-- 
______________________________________________________________________
Michael Sweet, Easy Software Products           mike at easysw dot com