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 focuses 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 exception: USB  Scanners  supported  by  the  sane-microtek2(5)
   backend need a special USB kernel driver.

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(1).  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(1) 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(1) is not permanent, however. They will be reset after reboot or replugging the scanner.

   Usually  udev(7) 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 direc
   tory tools/udev and tools/hotplug.  They can be used for setting permissions, see /usr/share/doc/libsane/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(1) to apply appropriate permissions.

SANE ISSUES

   This  section assumes that your scanner is detected by sane-find-scanner(1).  It doesn't make sense to go on, if this is not the case. While sane-find-scanner(1) 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 syn‐
   tax 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(1), 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.

   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  par
          ticular kernel versions. Example: export SANE_USB_WORKAROUND=1.

   SANE_XEROX_USB_HALT_WORKAROUND
          If  your  old  (pre-2010)  Xerox  / Samsung / HP scanner is detected only once and subsequent usage requires replugging the cable, try setting the environment variable SANE_XE
          ROX_USB_HALT_WORKAROUND to 1. This may work around issues which happen with particular USB controllers. Example: export SANE_XEROX_USB_HALT_WORKAROUND=1.

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)