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# sane-usb.5

    sane-usb(5)              SANE Scanner Access Now Easy              sane-usb(5)

## NAME

           sane-usb - USB configuration tips for SANE

## DESCRIPTION

           This  manual page contains information on how to access scanners with a
           USB interface. It focusses on two  main  topics:  getting  the  scanner
           detected by the operating system kernel and using it with SANE.

           This  page  applies  to USB most backends and scanners, as they use the
           generic sanei_usb interface. However,  there  is  one  exceptions:  USB
           Scanners  supported  by the microtek2 backend need a special USB kernel
           driver, see sane-microtek2(5) for details.

## QUICK START

           This is a short HOWTO-like section. For the full details, read the fol‐
           lowing  sections.  The  goal  of  this  section  is  to get the scanner
           detected by sane-find-scanner(1).

           Run sane-find-scanner. If it lists your scanner with the correct vendor
           and  product  ids, you are done. See section SANE ISSUES for details on
           how to go on.

           sane-find-scanner doesn't list your scanner? Does it work as  root?  If
           yes, there is a permission issue. See the LIBUSB section for details.

           Nothing  is found even as root? Check that your kernel supports USB and
           that libusb is installed (see section LIBUSB).

## USB ACCESS METHODS

           For accessing USB devices, the USB library libusb is used.  There  used
           to  exist  another  method  to  access  USB devices: the kernel scanner
           driver. The kernel scanner driver method is deprecated and shouldn't be
           used  anymore.  It  may be removed from SANE at any time. In Linux, the
           kernel scanner driver has been removed in the 2.6.* kernel series. Only
           libusb access is documented in this manual page.

## LIBUSB

           SANE  can  only  use libusb 0.1.6 or newer. It needs to be installed at
           build-time. Modern Linux distributions and other operating systems come
           with libusb.

           Libusb  can  only access your scanner if it's not claimed by the kernel
           scanner driver. If you want to use libusb,  unload  the  kernel  driver
           (e.g. rmmod scanner under Linux) or disable the driver when compiling a
           new kernel. For Linux, your kernel needs support for the USB filesystem
           (usbfs). For kernels older than 2.4.19, replace "usbfs" with "usbdevfs"
           because the name has changed. This filesystem must be  mounted.  That's
           done  automatically  at  boot  time, if /etc/fstab contains a line like
           this:

                  none /proc/bus/usb usbfs defaults  0  0

           The permissions for the device files used by libusb  must  be  adjusted
           for  user  access. Otherwise only root can use SANE devices. For Linux,
           the devices are located in /proc/bus/usb/ or in  /dev/bus/usb,  if  you
           use  udev.  There  are directories named e.g. "001" (the bus name) con‐
           taining files "001", "002" etc. (the device files).  The  right  device
           files can be found out by running scanimage -L as root. Setting permis‐
           sions with "chmod" is not permanent, however. They will be reset  after
           reboot or replugging the scanner.

           Usually udev or for older distributions the hotplug utilities are used,
           which support dynamic setting of access permissions.  SANE  comes  with
           udev and hotplug scripts in the directory tools/udev and tools/hotplug.
           They    can    be     used     for     setting     permissions,     see
           /usr/local/share/doc/sane-backends/README.linux,  tools/README  and the
           README in the tools/hotplug directory for more details.

           For the BSDs, the device files used by  libusb  are  named  /dev/ugen*.
           Use chmod to apply appropriate permissions.

## SANE ISSUES

           This  section  assumes that your scanner is detected by sane-find-scan‐
           ner. It doesn't make sense to go on, if this is  not  the  case.  While
           sane-find-scanner  is  able  to detect any USB scanner, actual scanning
           will only work if the scanner is supported by a SANE backend.  Informa‐
           tion  on  the  level  of  support  can  be  found  on  the SANE webpage
           (http://www.sane-project.org/), and the individual backend manpages.

           Most backends can detect USB scanners automatically using "usb" config‐
           uration  file lines. This method allows one to identify scanners by the
           USB vendor and product numbers.  The syntax for  specifying  a  scanner
           this way is:

                  usb VENDOR PRODUCT

           where VENDOR is the USB vendor id, and PRODUCT is the USB product id of
           the scanner. Both ids are non-negative integer numbers  in  decimal  or
           hexadecimal format. The correct values for these fields can be found by
           running sane-find-scanner, looking into the syslog (e.g., /var/log/mes‐
           sages)    or    under    Linux    by    issuing    the   command   "cat
           /proc/bus/usb/devices".  This is an example of a config file line:

                  usb 0x055f 0x0006

           would have the effect that all USB devices in the system with a  vendor
           id  of  0x55f and a product id of 0x0006 would be probed and recognized
           by the backend.

           If your scanner is not detected automatically, it may be  necessary  to
           edit  the  appropriate backend configuration file before using SANE for
           the first time.  For a detailed description of each backend's  configu‐
           ration  file,  please  refer  to the relevant backend manual page (e.g.
           sane-mustek_usb(5) for Mustek USB scanners).

           Do not create a symlink from /dev/scanner to  the  USB  device  because
           this  link is used by the SCSI backends. The scanner may be confused if
           it receives SCSI commands.

## ENVIRONMENT

           SANE_DEBUG_SANEI_USB
                  If the library was compiled with  debug  support  enabled,  this
                  environment  variable  controls  the debug level for the USB I/O
                  subsystem.  E.g., a value of 128 requests all debug output to be
                  printed.  Smaller levels reduce verbosity. Values greater than 4
                  enable  libusb  debugging  (if   available).   Example:   export
                  SANE_DEBUG_SANEI_USB=4.

## SEE ALSO

           sane(7), sane-find-scanner(1), sane-"backendname"(5), sane-scsi(5)

## AUTHOR

           Henning Meier-Geinitz <henning@meier-geinitz.de>

                                      14 Jul 2008                      sane-usb(5)