In FreeBSD, access to image scanners is provided by the SANE (Scanner Access Now Easy) API available through the FreeBSD Ports Collection. SANE will also use some FreeBSD device drivers to provide access to the scanner hardware.
FreeBSD supports both SCSI and USB scanners. Be sure the scanner is supported by SANE prior to performing any configuration. Refer to the supported devices list for more information about supported scanners.
Both SCSI and USB interfaces are supported. Depending upon the scanner interface, different device drivers are required.
The GENERIC kernel by default
includes the device drivers needed to support USB scanners.
Users with a custom kernel should ensure that the following
lines are present in the custom kernel configuration
file:
Plug in the USB scanner. Use dmesg(8) to determine whether the scanner appears in the system message buffer:
These messages indicate that the scanner is using
either /dev/ugen0.2 or
/dev/uscanner0, depending on the FreeBSD
version. For this example, a
EPSON
Perfection® 1650 USB scanner was used.
If the scanner uses a SCSI interface, it is important to
know which SCSI controller board it will use. Depending
upon the SCSI chipset, a custom kernel configuration file
may be needed. The GENERIC kernel
supports the most common SCSI controllers. Refer to
/usr/src/sys/conf/NOTES to determine
the correct line to add to a custom kernel configuration
file. In addition to the SCSI adapter driver, the following
lines are needed in the kernel configuration file:
Verify that the device is displayed in the system message buffer:
If the scanner was not powered-on at system boot, it is still possible to manually force the detection by performing a SCSI bus scan with the camcontrol(8) command:
# camcontrol rescan all
Re-scan of bus 0 was successful
Re-scan of bus 1 was successful
Re-scan of bus 2 was successful
Re-scan of bus 3 was successfulThe scanner should now appear in the SCSI devices list:
# camcontrol devlist
<IBM DDRS-34560 S97B> at scbus0 target 5 lun 0 (pass0,da0)
<IBM DDRS-34560 S97B> at scbus0 target 6 lun 0 (pass1,da1)
<AGFA SNAPSCAN 600 1.10> at scbus1 target 2 lun 0 (pass3)
<PHILIPS CDD3610 CD-R/RW 1.00> at scbus2 target 0 lun 0 (pass2,cd0)Refer to scsi(4) and camcontrol(8) for more details about SCSI devices on FreeBSD.
The SANE system is split in two
parts: the backends (graphics/sane-backends) and the
frontends (graphics/sane-frontends). The
backends provide access to the scanner. The
SANE's supported
devices list specifies which backend will support the
image scanner. The correct backend is needed in order to use
the scanner. The frontends provide the graphical scanning
interface, xscanimage.
After installing the graphics/sane-backends port or
package, use sane-find-scanner to check the
scanner detection by the
SANE system:
# sane-find-scanner -q
found SCSI scanner "AGFA SNAPSCAN 600 1.10" at /dev/pass3The output should show the interface type of the scanner and the device node used to attach the scanner to the system. The vendor and the product model may or may not appear.
Some USB scanners require firmware to be loaded. Refer to sane-find-scanner(1) and sane(7) for details.
Next, check if the scanner will be identified by a
scanning frontend. By default, the
SANE backends come with a command
line tool called scanimage(1). This command can be used
to list the devices and perform an image acquisition. Use
-L to list the scanner devices:
# scanimage -L
device `snapscan:/dev/pass3' is a AGFA SNAPSCAN 600 flatbed scannerHere is the output for the USB scanner used in Section 8.7.1.1, “USB Interface”:
# scanimage -L
device 'epson2:libusb:/dev/usb:/dev/ugen0.2' is a Epson GT-8200 flatbed scannerIn this output,
'epson2:libusb:/dev/usb:/dev/ugen0.2' is
the backend name (epson2) and the device
node (/dev/ugen0.2) used by the
scanner.
No output or a message saying that no scanners were
identified indicates that scanimage(1) is unable to
identify the scanner. If this happens, edit the backend
configuration file in /usr/local/etc/sane.d/
and define the scanner device used.
In the above example, the USB scanner is perfectly detected and working.
To determine if the scanner is correctly identified:
# scanimage -L
No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).Since the scanner is not identified, edit
/usr/local/etc/sane.d/epson2.conf. In
this example, the scanner model is
EPSON
Perfection® 1650 and it uses the
epson2 backend. When editing, read the
help comments in the backend configuration file. Line
changes are simple: comment out all lines that have the
wrong interface for the scanner. In this example, comment
out all lines starting with the word scsi
as the scanner uses the USB interface. Then, at the end
of the file, add a line specifying the interface and the
device node used. In this case, add the following
line:
Save the edits and verify that the scanner is identified:
# scanimage -L
device `epson:/dev/uscanner0' is a Epson GT-8200 flatbed scannerThe `epson:/dev/uscanner0' field now
gives the right backend name and the device node.
Once scanimage -L sees the scanner, the
configuration is complete and the device is now ready to
scan.
While scanimage(1) can be used to perform an image
acquisition from the command line, it is often preferable to
use a graphical interface to perform image scanning. The
graphics/sane-frontends
package or port installs a simple but efficient graphical
interface, xscanimage.
Xsane, which is installed with
the graphics/xsane package
or port, is another popular graphical scanning frontend. It
offers advanced features such as various scanning modes, color
correction, and batch scans. Both of these applications are
usable as a GIMP plugin.
In order to have access to the scanner, a user needs
read and write permissions to the device node used by the
scanner. In the previous example, the USB scanner uses the
device node /dev/ugen0.2 which is really a
symlink to the real device node
/dev/usb/0.2.0. The symlink and the device
node are owned, respectively, by the
wheel and
operator groups. Adding the user to
these groups will allow access to the scanner. However, for
security reasons, always think twice before adding a user
to any group, especially wheel. A better
solution is to create a group to make the scanner device
accessible to members of this group.
This example creates a group called
usb
# pw groupadd usbThen, make the /dev/ugen0.2 symlink
and the /dev/usb/0.2.0 device node
accessible to the usb group with write
permissions of (0660 or
0664. All of this is done by adding the
following lines to
/etc/devfs.rules:
Finally, add the users to
usb
# pw groupmod usb -m joeFor more details refer to pw(8).
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