[CLUE-Tech] USB trouble -- Solved (sorta)

[Matt Gushee]

Thanks to all who responded. I have the scanner working with the laptop,
but still no go on the desktop.

> Is it acceptable to install another kernel and just boot that image when 
> you want to do this work?

Gonna make me explain, huh? Unfortunately, I have everything but a
minimal root partition on ReiserFS, so a custom kernel is needed to run
applications and to have any significant storage space. Now that I think
about it, a stock kernel probably wouldn't make any difference, since it
appears the root cause is the unrecognized PCI device.

> >Box #2: laptop, 2.4.22 kernel
> >-----------------------------
> >Okay, here, as I said, it's closer to working. UHCI is compiled into the
> >kernel, and when I plug the scanner into the USB port and/or
> >
> Ok you've probably tried this already... but have you rebooted with the 
> scanner plugged in and/or tried running discover?  I have a feeling your 
> laptop is going to let you use the scanner before your desktop will.

Yep. What's 'discover,' by the way? Sounds like something I should know
about.

> > I will note that I have SANE 1.0.7 installed, whereas the "completely
> > supported" info was for SANE 1.0.14. So I may try a later version. But I
> > would expect that if the scanner is fully supported now, it would have
> > been at least partly supported a few minor releases back.
> Yes probably the mechanism to use the scanner is in the code and
> working, but the minor change between .7 and .14 may have been the
> vendor & product ids for the scanner you just bought.  Chances are that
> if it can't identify it as a known scanner, it won't play with it at
> all.  Does xsane-find-scanner say what *type* of scanner is found, or
> just that a *scanner* was was found?

Well, it showed a vendor and product ID all along. Maybe that's all it
needs to do.

> >  * /proc/bus/usb exists but contains no files. Should it? This Debian
> >    package of SANE depends on libusb, which (I have the impression) is
> >    supposed to be an alternative to the /proc/bus/usb mechanism, so
> >    maybe that's okay.
> If the library is in userland, I doubt it actually updates the /proc
> system.

That's what I thought, but apparently the /proc/... stuff is necessary.

> Matt>  # modprobe usb-ohci
> 
> Matt> I get "no such device" errors. I'm not positive it uses
> Matt> OHCI--haven't found any docs on that yet--but since the chipset
> Matt> is Compaq (?), I'm guessing it does. In any case, I get the same
> Matt> errors with both uhci and usb-uhci modules.
> 
> Right. The linux kernel didn't add USB2 support until 2.4.19. 
> So, your kernel is too old. ;) 

Oops. Didn't think of that.

> Can you upgrade to a more recent one?
> Anything 2.4.19 and higher should have the ehci-hcd usb2 driver. 

Yep. My approach to kernels is basically "if it ain't broke, don't fix
it," but since the status quo was clearly broken, I'm now running a
2.4.26 kernel. Unfortunately, that USB adapter is still unrecognized.

> Matt>  * /proc/bus/usb exists but contains no files. Should it? This
> Matt> Debian package of SANE depends on libusb, which (I have the
> Matt> impression) is supposed to be an alternative to the
> Matt> /proc/bus/usb mechanism, so maybe that's okay.
> 
> Yeah, there should be files, thats a usbdevfs virtual filesystem. 
> Try: 
> 
> mount -t usbdevfs usbdevfs /proc/bus/usb

Dohh! Shoulda known that one.

As it turns out, I had to mount /proc/bus/usb AND upgrade to SANE-1.0.14
to get the scanner working with the laptop. Now if I could just figure
out what to do with the damn USB adapter on the desktop ...

-- 
Matt Gushee                 When a nation follows the Way,
Englewood, Colorado, USA    Horses bear manure through
mgushee at havenrock.com           its fields;
http://www.havenrock.com/   When a nation ignores the Way,
                            Horses bear soldiers through
                                its streets.
                                
                            --Lao Tzu (Peter Merel, trans.)