(Re-posting this under new section because I got no reply under Hardware.)

Info : KDE 3.1-10
Linux : 2.4.20-20.9
Machine : i686 (Athlon AMD)
Scanner : Vuego USB (unknown type)

Problem : Occasionaly (I can't predict it) the scanner will just stop working
and Xsane gives me the error:
Failed to open "snapscan:/dev/usb/scanner0" : invalid argument.

If I restart (or power-down and power-up) the machine the problem is still
there. If I restart and boot into XP and use the scanner from there (which works
every time) and then restart and boot back into Linux, the scanner is suddenly
working again...?
Wild but true!

No amount of rooting about at the command line has helped me.
I have tried all the "scanimage" commands and man sane-xxxx and
none of it helps me identify what is going on.
Running Xsane as root has no effect either.
Killing all the config files in ~/.sane/xsane/ to try force a 'rescan' of some kind has no effect.
Anyone out there have some clue?

The same kind of thing happened to my modem yesterday. I could not dial-out (it said "No carrier detected") but when I booted Windows, dialled-up fine, rebooted Linux, suddenly it was ok again... ? ?

Thanks
Biggles
(serious newbie)

Other info:
-----------
dmesg | grep USB:
-----------------
ehci-hcd 00:10.3: VIA Technologies, Inc. USB 2.0
usb.c: new USB bus registered, assigned bus number 1
ehci-hcd 00:10.3: USB 2.0 enabled, EHCI 1.00, driver 2003-Jan-22
hub.c: USB hub found
usb-uhci.c: USB UHCI at I/O 0xd000, IRQ 10
usb.c: new USB bus registered, assigned bus number 2
hub.c: USB hub found
usb-uhci.c: USB UHCI at I/O 0xd400, IRQ 10
usb.c: new USB bus registered, assigned bus number 3
hub.c: USB hub found
usb-uhci.c: USB UHCI at I/O 0xd800, IRQ 11
usb.c: new USB bus registered, assigned bus number 4
hub.c: USB hub found
usb-uhci.c: v1.275:USB Universal Host Controller Interface driver
hid-core.c: USB HID support drivers
hub.c: new USB device 00:10.1-2, assigned address 2
usb.c: USB device 2 (vend/prod 0x4a5/0x20b0) is not claimed by any active
driver.scanner.c: USB scanner device (0x04a5/0x20b0) now attached to scanner0
scanner.c: 0.4.12:USB Scanner Driver

Shows that the scanner is seen by linux and is set to 'scanner0'
- despite this, Xsane will not work.

scanimage -L:
-------------
device `snapscan:/dev/usb/scanner0' is a Acer FlatbedScanner22 flatbed scanner


sane-find-scanner:
------------------
# No SCSI scanners found. If you expected something different, make sure that
# you have loaded a SCSI driver for your SCSI adapter.

found USB scanner (vendor=0x04a5, product=0x20b0) at /dev/usb/scanner0
found USB scanner (vendor=0x04a5 [Color], product=0x20b0 [ FlatbedScanner 22])
at libusb:003:002 # A USB device was detected. This program can't be sure if
it's really # a scanner. If it is your scanner, it may or may not be supported
by # SANE. Try scanimage -L and read the backend's manpage.

# Scanners connected to the parallel port or other proprietary ports can't be
# detected by this program.


scanimage:
----------
[snapscan] download_firmware: No firmware entry found in config file
snapscan.conf.scanimage: open of device snapscan:/dev/usb/scanner0 failed:
Invalid argument

There the wonders of the wonderful USB. When you exit to windows by rebooting of course the scanner will work. When you reboot back to Linux same thing got nought to do with Windows or Linux. That's USB and the power supply to USB. It is a crap system anway.

Buttersoft,
If you read my post you would see that I did reboot Linux --> Linux and it made no difference. I also powered-down the entire system (scanner and all from the wall plug) for over 12 hours and then restarted - it did NOT work.

BUT - after I boot into Windows, suddenly the scanner (and the modem) works again.
Huh?
This is very disturbing and a real Linux-breaker in my book...

Before jumping to conclusions
What kernel are you using?

uname -r
at a console.
If it's not 2.6, upgrade to 2.6 That should fix the USB problem.

Must be too early. I have a scsi scanner, gives no such problems. I have experienced a lot of hassle with my usb stuff: speakers, mouse and keyboard. Which I recently solved by introducing a powered hub. I don't like USB, I find the plugs a pain.

So sorry next time I will read fully the post. Teval suggests upgrade kernel to 2.6, I thought that was not yet out?

Bigglesworth,

Aren't you at fault for using an unknown type of scanner, rather than buying equipment that is hardware listed as working with Linux? Especially when the unit is a USB one, as USB does not have the greatest of records of being supported?

Vuego USB (unknown type)

Kernel 2.4.20-20.9 (as in my post *sigh* )
"Teval suggests upgrade kernel to 2.6, I thought that was not yet out?"
> Yeah - so did I...
Also, that's difficult for me because of my little 56k modem and weekend-only dial time.

The thing is my modem is not USB (it's serial) and the same kind of Window restart fix thing applies to it.

It's the damndest thing ever - and just when I thought I had put XP behind me!

Buttersoft,
I confess that my scanner is 100% pure concentrated crap - but it does work via Xsane quite often - no problems, until that fatefull *unknown* situation when I then have to restart via XP to "kick" it back into line...

Bet it was cheap though!

Which is the mistake everyone is being encouraged to make.

Cheap doesn't always work.

It was all I could afford.
My modem, however, was not cheap and it's not USB - so how would you explain that?

My thinking is that there is some condition that "locks" the peripherals (although my printer has not suffered) and when Windows boots it somehow "resets" them again?
Is this even remotely possible?

All I could afford. Ah, I know that feeling.

Are there any other places I could ask this question? Perhaps this is the wrong forum?

[Disclaimer: if you try this you may break stuff]

I assume you've checked this, but I'll ask anyway.

I had a cheap scanner that "hung". It would scan fine for a while, then just not respond. It turned out (after running it with the casing off) that the scanning head wasn't always returning to it's start position after a scan. It was only out by a few mm, but enough to throw the software.

Fixes I tried:
(very) light coat of WD40 on the guide rails <---worked for a while.
placing scanner so that the "head return end" was downhill (i.e. a book under the other end). <--- in combination with the above, pretty much solved it.

Eventually bought a better scanner with a steel, rather than rubber drive cable.

Frogman,
Good suggestion - I never thought to check this as the problem immediately dissolves upon booting into Windows - I do not touch the scanner at all.
However I will check it out and try some lubrication - perhaps that's crashing Linux software but Windows software is catering for such a problem. (Esp. as the driver that comes with it is for Windows!)

Thanks though.