Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
sane-usb(5)		 SANE Scanner Access Now Easy		   sane-usb(5)

       sane-usb	- USB configuration tips for SANE

       This  manual page contains information on how to	access scanners	with a
       USB interface. It focuses 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 exception: USB Scan-
       ners supported by the sane-microtek2(5) backend need a special USB ker-
       nel driver.

       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(1).  If it	lists your scanner  with  the  correct
       vendor  and  product ids, you are done. See section SANE	ISSUES for de-
       tails 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 de-

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

       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.

       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

	      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  per-
       missions	 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  directory  tools/udev   and
       tools/hotplug.	They can be used for setting permissions, see /usr/lo-
       cal/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.

       This section assumes that your scanner is detected  by  sane-find-scan-
       ner(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. Informa-
       tion on the  level  of  support	can  be	 found	on  the	 SANE  webpage
       (, 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:


       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 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.

	      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-

	      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.

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

       Henning Meier-Geinitz <>

				  14 Jul 2008			   sane-usb(5)


Want to link to this manual page? Use this URL:

home | help