Your scanner works on Linux
Benq 5000 scanner for example
Introduction
In this article I'll show you how to get your scanner to work on GNU/Linux.
I'm using several Linux distributions, like Ubuntu 7.04 and Fedora Core 5.0,
but this procedure should work on any recent Linux kernel having the udev system enabled.
I'm discussing BenQ 5000 USB scanner, other scanners should be similar.
There are three important issues about scanners, 1st is to have the user-land back-end driver for it,
2nd is to have the firmware file loaded into the scanner if needed, and the last step is to set permission correctly.
In Linux we have a SANE system for scanners,
which is a multi-platform scanning system (as opposed to TWAIN system in MS-Windows).
SANE is short for Scanner Access Now Easy.
And we have several ways to utilize it, of course first of all, we have the command line utilities,
and we have the GTK+ graphical interface called XSANE and the QT graphical interface for KDE
which is called "Quite insane!" (despite the name it's very nice)
and many others.
Of course, you know GIMP, the best Image editing tool I know.
it got plug-ins to use both XSANE and "Quite insane", but in most cases only the first
is installed by default.
You find them under File -> Acquire menu in the main GIMP window (the one with the tools box).
Detection
You can see all the USB devices by examining the contents of
/proc/bus/usb/devices pseudo file. Because we are looking for a scanner
I'm going to search that file for the word "Scan" and displaying the surrounding context,
you may use GUI text editors, but Why bothering?! a single command line do that
(type onlt the bold text line just after the prompt of "bash$")
bash$ grep -A6 -B5 -i 'Scan' /proc/bus/usb/devices
T: Bus=05 Lev=01 Prnt=01 Port=04 Cnt=01 Dev#= 6 Spd=480 MxCh= 0
D: Ver= 1.00 Cls=ff(vend.) Sub=ff Prot=ff MxPS= 8 #Cfgs= 1
P: Vendor=04a5 ProdID=20f8 Rev= 1.15
S: Manufacturer=Color
S: Product= FlatbedScanner 22
C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
E: Ad=81(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 8 Ivl=0ms
E: Ad=83(I) Atr=03(Int.) MxPS= 8 Ivl=16ms
bash$ cat /sys/class/usb_device/usbdev5.6/device/product
FlatbedScanner 22
bash$ cat /sys/class/usb_device/usbdev5.6/device/idProduct
20f8
bash$ udevinfo -q path -n bus/usb/005/006
/class/usb_device/usbdev5.6
bash$ udevinfo -q all -p /class/usb_device/usbdev5.6
P: /class/usb_device/usbdev5.6
N: bus/usb/005/006
S: scanner-usbdev5.6
bash$ udevinfo -a -p /class/usb_device/usbdev5.6 | less
... display long information
That was the kernel, but one should have a user-land tool to ask for images,
It's the SANE back-end.
If every thing is fine then the command line tool scaneimage
should be able to detect the scanner by using the -L option,
at least as root (super user). First be root (by typing "su" then root password or if you have turned off the root account as in Ubunto type "sudo su" or "sudo -i" followed by your password)
then try the following two commands (only the bold text after the root Bash prompt bash#)
bash# scanimage -L
device `snapscan:libusb:005:006' is a Acer FlatbedScanner22 flatbed scanner
bash# sane-find-scanner
#... long long tips ...
found USB scanner (vendor=0x04a5 [Color], product=0x20f8 [ FlatbedScanner 22]) at libusb:005:006
#... long long tips ...
Firmware loading
First let's know which is the SANE back-end (driver) we need to use by searching
for the name "BenQ" or better the Product ID of our scanner (which is 20f8 in our case)
bash$ grep -i '20f8' /etc/sane.d/*
/etc/sane.d/snapscan.conf:usb 0x04a5 0x20f8
It's not very hard to get the firmware, put the CD that come with the scanner and mount it then
locate a .bin file on it (usually named after the Product ID and revision number)
to do that I use this command (you may need to replace /media/cdrom0 with the yours own one)
bash$ cd /media/cdrom0
bash$ find ./ -iname '*.bin'
...
./driver/bin/20f8v115.bin
...
bash# mkdir -p /usr/share/sane/snapscan/
bash# cp -v driver/bin/20f8v115.bin /usr/share/sane/snapscan/
Now we have to tell the driver were did we put the firmware,
open the back-end configuration file (which is /etc/sane.d/snapscan.conf) in your favorite text editor (you need super user privileges for it, run for example "gksu gedit /etc/sane.d/snapscan.conf" or with "gksudo" instead of "gksu" to the rest of the command if root is turned off)
to fix this line (which usually point to non-existing file) to point to our firmware
firmware /usr/share/sane/snapscan/20f8v115.bin
Access and Permissions
Of course, scanning is not something you do as root, so the last two commands should
also work as regular user but because the default permissions given to the
device files corresponding to the USB scanner were so restrictive
you can't.
bash$ 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).
bash# chown root:scanner /dev/bus/usb/005/006 /proc/bus/usb/005/006
bash# chmod 664 /dev/bus/usb/005/006 /proc/bus/usb/005/006
To have do it right, you should set the udev rules correctly,
we have already have rules for scanners in most distribution,
the file is called /etc/udev/rules.d/??-libsane.rules
(where ?? are two digits, in Fedora Core it's 60, in Ubuntu it's 45)
this file should have an entry for our scanner
in order to implement the distribution policy on the device files,
in Fedora Core the file /etc/udev/rules.d/60-libsane.rules
add an entry like following one after the line of any other scanner
(just duplicate a previous line then modify the IDs)
SYSFS{idVendor}=="04a5", SYSFS{idProduct}=="20f8", SYMLINK+="scanner-%k"
SYSFS{idVendor}=="04a5", SYSFS{idProduct}=="20f8", MODE="664", GROUP="scanner"
Enjoy Scanning
After we have played with Linux kernel, and practiced some commands
it's time for you to restart your computer (not needed but as I want to make sure that the changes are permenent)
and enjoy scanning.
XSANE is very crowded, you should start looking at preview window (if it's not there, show it from the XSANE main window from Windows -> Preview or something like that).
There are too many options in XSANE, some are specific to your scanner back-end,
others are for all scanners and so on.
But because I'm too comfortable with GIMP, I just preview then select the area which I want to scan,
then set the resolution then just scan. After that I do all the editing inside GIMP (although XSANE is very rich with tools)
There are a very useful feature called "batch scanning" which enable you to scan several
different pictures (rectangles) in one pass.
Sometimes you may think that XSANE is frozen or hanged but this is not true,
when I run the command line tool I've got this
[snapscan] Scanner warming up - waiting 21 seconds.
SANE got some features that I can't think that there is someone on earth uses them,
like scanning over a network by running SANE daemon! (this feature is turned off or even not included in most distributions)
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