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SANE cannot find any scanners

As I upgrade to 13.10 of Ubuntu, I'm having to do work to get my system back to normal...

Today I stumble on the fact that USB ports are now not accessible by everyone by default. So when I tried to scan a document, it told me that I had no scanner. Panic... and then I found out that the permissions were changed, widely, so only users who are root (by default) can access the scanner.

I changed the group to a group I'm in and it worked without having to reboot or relog in. However, it is not unlikely that the group won't stick... TBD!

To find the USB port that has your scanner, use the following command:

sudo sane-find-scanner

When you are root, it can scan all the USB ports in read and write mode so it will be capable of finding the port. You will get an entry such as:

found USB scanner (vendor=0x04b8 [EPSON], product=0x011d [EPSON Scanner]) at libusb:003:002

Here we see that the USB port in question is 003 / 002. You should know the name of the vendor which should help you find the correct port.

The port definition is found under /dev/bus/usb, in my case I could do:

ls -l /dev/bus/usb/003

The entry of interest showed up in the list:

crw-rw-r--  1 root root 189, 256 Mar  4 19:43 001
crw-rw-r--+ 1 root root 189, 257 Mar  4 19:43 002

As we can see, the owner and group are set to root. Also you may notice a + next to the standard Unix flags. I'm not sure what that is though. Maybe a "signal" that something is connected on that port.

So to change the group I used the chgrp command:

sudo chgrp lpadmin /dev/bus/usb/003/002

Again you have to use sudo. Here I used lpadmin which is a group I am defined in. To see the list of group you pertain to use the groups command:

groups

Once that is done, the sane-find-scanner should work as you, instead of root. This mean you should be able to do that and see your scanner in the list:

sane-find-scanner

If so, then you are back in business. But only until the next time you restart your computer or disconnect / reconnect your scanner (I unplug the power of my scanner when I don't use it, less electricity!) Thus we need a way to have that lpadmin stick around. For that, I use the following:

# Make my EPSON accessible without having to sudo chgrp each time I use it
SUBSYSTEM=="usb|usb_device",ATTRS{idVendor}=="04b8",ATTRS{idProduct}=="011d",GROUP="lpadmin"

Make sure to change the vendor number (04b8 for my Epson) and the product number (011d for my Epson) to your device numbers. If you look closely, they are shown when you run the sane-find-scanner tool. For additional features available in the udev rule files, check the system files under /lib/udev/rules.d, there are many there.

This is put in a file under /etc/udev/rules.d/... The name of the file should start with a 2 digits number. For example:

50-epsonusb.rules

Just like with other things under /etc, you'll need to use sudo to edit that file:

sudo vim /etc/udev/rules.d/50-epsonusb.rules

One cool thing though, now I can run the scans in the background and it works! In 12.10 it used to fail in the background...

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