lsusb
...
Bus 002 Device 003: ID 04a9:2204 Canon, Inc. CanoScan FB630U
...
sane-find-scanner
...
found USB scanner (vendor=0x04a9, product=0x2204 [CanoScan FB630U]) at libusb:002:003
...
scanimage -L (xsane not running)
device `canon630u:libusb:002:003' is a CANON Canoscan FB630U flatbed scanner
scanimage -L (xsane running)
No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).
tail -f /var/log/syslog (on start of xsane)
...
Apr 30 21:40:29 hb xsane: unable to open /var/run/hplip/hpiod.port: No such file or directory: api/hplip_api.c 93
Apr 30 21:40:29 hb xsane: unable to connect hpiod socket 2208: Connection refused: api/hplip_api.c 721
Exactly the same behaviour here.
lsusb
...
Bus 002 Device 003: ID 04a9:2204 Canon, Inc. CanoScan FB630U
...
sane-find-scanner
...
found USB scanner (vendor=0x04a9, product=0x2204 [CanoScan FB630U]) at libusb:002:003
...
scanimage -L (xsane not running) libusb: 002:003' is a CANON Canoscan FB630U flatbed scanner
device `canon630u:
scanimage -L (xsane running)
No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).
xsane Info: libusb: 002
Vendor: CANON
Model: Canoscan FB630U
Type: flatbed scanner
Device: 003
Loaded backend: canon630u:
Sane version: 1.0.18
...
tail -f /var/log/syslog (on start of xsane) hplip/hpiod. port: No such file or directory: api/hplip_api.c 93
...
Apr 30 21:40:29 hb xsane: unable to open /var/run/
Apr 30 21:40:29 hb xsane: unable to connect hpiod socket 2208: Connection refused: api/hplip_api.c 721
??? Why does xsane try to open hplip?
Without help this is as much as I can find out.