Information about USB scanners: ================================ With Linux 2.4.* you could either use the kernel scanner module or libusb to access USB scanners. In Linux 2.6.4 the kernel scanner module was removed. Therefore with this and later kernels libusb must be used. While SANE automatically uses libusb when the library and its header file were present during the build of sane-backends, setting permissions will require some attention. So if scanimage -L lists your scanner as root but not as normal user read on this text. The device files used by libusb are located in /proc/bus/usb/ (e.g. /proc/bus/usb/001/003). The exact file name can be found out by running sane-find-scanner which would print "libusb:001:003" in this case. While setting permissions with e.g. "chmod a+rw /proc/bus/usb/001/003" works, this change is not permanent. The permissions will be reset when the scanner is replugged or Linux is rebooted. One solution to set permissions on-the-fly are the Linux hot-plug tools that should come with any current distribution. Your distribution should have set up the scripts to automatically change permissions correctly. Look for "libsane.usermap" and "libusbscanner" in /etc/hotplug/usb. Usually you must just add the users that are allowed to access the scanner to group "scanner". To make that change active, the user must login again. For more details, see your distribution's documentation e.g. for Debian: README.debian.gz. If you build SANE from source you can use the hotplug script that comes with SANE. See the tools/hotplug/ directory in the source distribution. Please refer to the README in that directory for the details. Gentoo users: If your USB scanner is not detected at all check that USE=usb is set when emerging. Information about SCSI scanners: ================================ Under Linux, your kernel must have generic SCSI support (sg) as well as a driver for your SCSI adapter. You may want to increase the SCSI buffer size to increase scan speed. Details on all of the above can be found in sane-scsi(5). If your SCSI and sg driver are build as moduls you will need to load them with modprobe: # modprobe your-driver-name # modprobe sg You may find error messages in /var/log/messages. Look at the documentation for your SCSI driver. Maybe you need to add options like the io port. Now the SCSI adapter and your scanner should be visible at /proc/scsi/scsi. Example: # cat /proc/scsi/scsi Host: scsi0 Channel: 00 Id: 06 Lun: 00 Vendor: SCANNER Model: Rev: 2.02 Type: Scanner ANSI SCSI revision: 01 CCS In this case the real vendor and scanner name are not shown (Mustek Scannexpress 12000SP) but SANE will detect it nevertheless. If your scanner is supported by SANE, scanimage -L will list it now: # scanimage -L device mustek:/dev/scanner' is a Mustek ScanExpress 12000SP flatbed scanner If this doesn't work you may have to add the right SCSI generic device name to the configuration file. This should be documented in the man page for your backend. To find out about the right SCSI device use sane-find-scanner: # sane-find-scanner found SCSI scanner "SCANNER 2.02" at /dev/scanner found SCSI scanner "SCANNER 2.02" at /dev/sg0 found SCSI scanner "SCANNER 2.02" at /dev/sga It may help to set a symbolic link /dev/scanner to the respective device if automatic detection does not work. If you need more information on the Linux SCSI subsystem, look at http://www.torque.net/scsi/linux_scsi_24/index.html. Although this documentation is about the 2.4 kernels, large parts are also valid for older kernels. One important exception is the section on "Device Names in devfs". Adaptec 1542 SCSI adapter: Using buffer sizes of more than 32768 bytes with the aha1542 driver can lead to kernel panic with older kernels. To avoid this, run configure with the option --enable-scsibuffersize or set the environment variable SANE_SG_BUFFERSIZE to 32768 before running scanimage or another frontend, or download and install the SG driver 2.1.37 or newer from http://www.torque.net/sg. idescsi: The Linux kernel "Emulation of a SCSI host adapter for IDE ATAPI devices" (idescsi) is reported to cause problems in connection with SANE. If your scanner isn't found or you encounter segmentation faults try to disable idescsi. SCSI Direct IO: Recent versions of the Linux SG driver for the 2.4 kernels support direct IO, i.e., the SCSI adapter's DMA chip copies data directly to/from user memory. Direct IO reduces memory usage, but it can lead to access conflicts, if a backend uses shared memory. SANE does not use direct IO by default. If you want to use it, run configure --enable-scsi-directio=yes Very old Linux distributions are missing the /usr/include/scsi directory. In such a case, it is necessary to copy the relevant files from the kernel distribution. Normally, the command: cp -a /usr/src/linux/include/scsi /usr/include should fix this problem. Don't do this if you don't get compilation errors about missing SCSI headers. Other Information ================= Excessive warnings "pointer of type `void *' used in arithmetic": Some older versions of glibc generate these warnings not related to SANE source code. To suppress these warnings do export CFLAGS="-g -O2 -D__NO_STRING_INLINES" and rerun configure. If you use DEC cc on Linux Alpha, you may need to set LDFLAGS="-N" to be able to build sane-backends. The Intel C++ Compiler for IA32 and IA64 isn't supported yet. If you want to try nevertheless, you will experience undefined references to inb and outb functions. To avoid those replace #include with #if defined(__ICC) && __ICC >= 700 # define __GNUC__ 2 #endif #include #if defined(__ICC) && __ICC >= 700 # undef __GNUC__ #elif defined(__ICC) && defined(HAVE_ASM_IO_H) # include #endif