Ubuntu Manpage: sane-usb - USB configuration tips for SANE

Provided by: libsane-common_1.0.27-1~experimental3ubuntu2.4_all

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 following 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) 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 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 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-scanner. 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. Information 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" configuration 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/messages) 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
configuration 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.

AUTHOR

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

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