[sane-devel] Problem in detecting usb scanner

[Giuseppe Sacco]

Hi all,
I am testing once again a new linux kernel for mips architecture (both
2.6.26-rc9 and 2.6.26.1). On this machine (SGI O2) I am trying an usb
scanner (epson perfection 1670) without luck, but I suspect something is
missing among kernel modules.

 currently installed SANE is
giuseppe at sgi:~$ LC_LANG=C dpkg -l \*sane\* | grep ^ii
ii  libsane                1.0.18-5       API library for scanners
ii  sane                   1.0.14-2       scanner graphical frontends
ii  sane-utils             1.0.18-5       API library for scanners -- utilities

What happens:
 when I plug in the usb cable, I get those new lines in syslog:
[17221259.260000] usb 3-2: new high speed USB device using ehci_hcd and address 2
[17221259.440000] usb 3-2: configuration #1 chosen from 1 choice
[17221259.496000] usb 3-2: New USB device found, idVendor=04b8, idProduct=011f
[17221259.532000] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[17221259.564000] usb 3-2: Product: EPSON Scanner
[17221259.596000] usb 3-2: Manufacturer: EPSON

 then a new device appears as /dev/bus/usb/003/002. This device is
correctly owned by scanner group, so udev communicate with the scanner
and correctly get vendor/product
giuseppe at sgi:~$ find /dev/bus/usb/ -ls
  1671    0 drwxr-xr-x   5 root     root          100 ago  3  2008 /dev/bus/usb/
  1699    0 drwxr-xr-x   2 root     root           80 ago  3 19:15 /dev/bus/usb/003
207260    0 crw-rw-r--   1 root     scanner           ago  3 19:15 /dev/bus/usb/003/002
  1700    0 crw-rw-r--   1 root     root              ago  3 19:17 /dev/bus/usb/003/001
  1691    0 drwxr-xr-x   2 root     root           60 ago  3  2008 /dev/bus/usb/002
  1692    0 crw-rw-r--   1 root     root              ago  3 19:17 /dev/bus/usb/002/001
  1672    0 drwxr-xr-x   2 root     root           60 ago  3  2008 /dev/bus/usb/001
  1673    0 crw-rw-r--   1 root     root              ago  3 19:17 /dev/bus/usb/001/001

 libusb might use /proc/bus/usb instead of /dev/bus/usb, so check it:
giuseppe at sgi:~$ find /proc/bus/usb/ -ls
  1430    0 drwxr-xr-x   5 root     root            0 ago  3 21:19 /proc/bus/usb/
  1486    0 dr-xr-xr-x   2 root     root            0 ago  3 21:19 /proc/bus/usb/003
207166    0 -rw-r--r--   1 root     root           57 ago  3 19:15 /proc/bus/usb/003/002
  1490    0 -rw-r--r--   1 root     root           43 ago  3 21:19 /proc/bus/usb/003/001
  1474    0 dr-xr-xr-x   2 root     root            0 ago  3 21:19 /proc/bus/usb/002
  1482    0 -rw-r--r--   1 root     root           43 ago  3 21:19 /proc/bus/usb/002/001
  1432    0 dr-xr-xr-x   2 root     root            0 ago  3 21:19 /proc/bus/usb/001
  1470    0 -rw-r--r--   1 root     root           43 ago  3 21:19 /proc/bus/usb/001/001
  1431    0 -r--r--r--   1 root     root            0 ago  3 19:15 /proc/bus/usb/devices

 why /proc/bus/usb/003/002 is not owned by scanner group?

 sane-find-scanner doesn't find any scanner. Logging sanei_usb I see:
giuseppe at sgi:~$ env SANE_DEBUG_SANEI_USB=255 sane-find-scanner
[sanei_debug] Setting debug level of sanei_usb to 255.
[sanei_usb] sanei_usb_init: Looking for kernel scanner devices
[sanei_usb] sanei_usb_init: can't stat /dev/usb/: No such file or directory
[sanei_usb] sanei_usb_init: Looking for libusb devices
usb_set_debug: Setting debugging level to 255 (on)
usb_os_find_busses: Found 003
usb_os_find_busses: Found 002
usb_os_find_busses: Found 001
usb_os_find_devices: Couldn't open /dev/bus/usb/003/002
usb_os_find_devices: couldn't get connect info
[...]

 currently loaded modules are:
giuseppe at sgi:~$ lsmod | egrep 'usb|hcd'
ehci_hcd               64240  0 
ohci_hcd               37040  0 
usbcore               223696  3 ehci_hcd,ohci_hcd

 finally, why lsusb does not list the scanner?
giuseppe at sgi:~$ lsusb
Bus 003 Device 001: ID 1d6b:0001  
Bus 002 Device 001: ID 1d6b:0001  
Bus 001 Device 001: ID 1d6b:0001  
giuseppe at sgi:~$ sudo lsusb
Password:
Bus 003 Device 001: ID 1d6b:0001  
Bus 002 Device 001: ID 1d6b:0001  
Bus 001 Device 001: ID 1d6b:0001  

Many thanks to all,
Giuseppe