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  most  backends  and  scanners, as they use the
       generic sanei_usb interface. However, there are  some  exceptions:  USB
       Scanners  supported  by the microtek2 backend need a special USB kernel
       driver, see sane-microtek2(5) for details. The sm3600 backend  accesses
       scanners over libusb dierctly. See the appropriate section in this man-
       page and sane-sm3600(5).


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 LIBSUB 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/. There are directories  named
       e.g.  "001"  (the  bus  name)  containing  files "001", "002" etc. (the
       device files). The right device files  can  be  found  out  by  running
       scanimage  -L  as  root. Setting permissions with "chmod" is not perma-
       nent, however. They will be reset after reboot or replugging the  scan-
       ner.

       Usually   the   the   hotplug  utilities  (http://linux-hotplug.source-
       forge.net/) are used, which support dynamic setting of  access  permis-
       sions.  SANE comes with hotplug scripts in the directory tools/hotplug.
       They can be used for setting permissions.   Precompiled  SANE  packages
       may have already installed such hotplug scrips in /etc/hotplug/.

       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 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>

sane-backends 1.0.16              29 May 2005                      sane-usb(5)

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