sane-usb

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  de-
       tected 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 de-
       tected 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  @DOCDIR@/README.linux,
       tools/README and the README in the tools/hotplug directory for more de-
       tails.

       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/de-
       vices".  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 en-
              vironment variable controls the debug level for the USB I/O sub-
              system.  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_DE-
              BUG_SANEI_USB=4.

       SANE_USB_WORKAROUND
              If your scanner does not work when plugged into a USB3 port, try
              setting the environment variable SANE_USB_WORKAROUND to 1.  This
              may  work around issues which happen with particular kernel ver-
              sions. Example: export SANE_USB_WORKAROUND=1.

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

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

@PACKAGEVERSION@                  14 Jul 2008                      sane-usb(5)