Q: Canon CanoScan LiDE 25 Ubuntu 14.04 lts Failed to Scan I am attempting to get any scanner to work on Ubuntu 14.04 lts. I'm currently attempting to run a Canon CanoScan LiDE 25. I have tried both XSane and Simple Scan. I've tried running from Terminal with sudo. Scanners are recognized in Simple Scan, but will not scan. For the sake of simplicity I will only focus on the Canon scanner at this time.
Canon CanoScan LiDE 25 


*

*Type: Flatbed

*Scanning Element: CIS (Color Contact Image Sensor)

*Light Source: 3-color (RGB) LED

*Optical Resolution: 1200x2400 dpi

*Selectable Resolution: 25-19200 dpi (ScanGear CS)

*Interface: USB 1.1

*Power Consumptions: In operation: 2.5watts maximum, Stand by:
1.4watts


My Machine: HP Pavilion g6 


*

*Processor: 4x Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz

*Memory: 3937MB (1217MB used)

*OS: Ubuntu 14.04.2 LTS

*Resolution: 1366x768 pixels


I've uploaded a screenshot of the issue (XSane lower right window, Simple Scan on the left with a Terminal window open and showing the scanner is recognized) which you can find linked here via my GDrive.
In the research I have done I've heard whispers of permissions issues, USB incompatibility and a "there is no backend" issue via this Linux Blog. I have no idea where to go next with this and could use the help.
Thanks very much for looking and any input and/or advice.

A: I use Canon CanoScan LiDE 25 and recently tried to scan again using Simple Scan. While the scanner always works for 32-bit system, it had failed work at all for 64-bit system. I have confirmed these results while running Xubuntu 14.04.
Proof of failed attempts
In the following attempts, I connect the scanner to USB 3.0 and 2.0 ports in turns and run lsusb and dmesg | tail commands in Terminal to confirm it is being detected. The output lines have been trimmed to show the relevant ones only.
Attempt 1. Use USB 3.0 port to connect the scanner (Detect: YES, Scan: FAILED)

$  lsusb
Bus 001 Device 011: ID 04a9:2220 Canon, Inc. CanoScan LIDE 25
$  dmesg | tail
[  719.578197] usb 1-1: new full-speed USB device number 11 using xhci_hcd
[  719.596841] usb 1-1: New USB device found, idVendor=04a9, idProduct=2220
[  719.596863] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  719.596878] usb 1-1: Product: CanoScan
[  719.596890] usb 1-1: Manufacturer: Canon
[  719.669064] WARNING! power/level is deprecated; use power/control instead

Attempt 2. Use USB 2.0 port to connect the scanner (Detect: YES, Scan: FAILED)

$  lsusb
Bus 001 Device 012: ID 04a9:2220 Canon, Inc. CanoScan LIDE 25
$  dmesg | tail
[  719.669064] WARNING! power/level is deprecated; use power/control instead
[  898.267099] usb 1-1: USB disconnect, device number 11
[  905.255202] usb 1-4.3: new full-speed USB device number 12 using xhci_hcd
[  905.273163] usb 1-4.3: New USB device found, idVendor=04a9, idProduct=2220
[  905.273186] usb 1-4.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  905.273201] usb 1-4.3: Product: CanoScan
[  905.273214] usb 1-4.3: Manufacturer: Canon

Why did not work
I read somewhere that the presence of USB 3.0/XHCI may interfere the use of scanner. This didn't make much sense to me, so I just tried changing the ports without disabling any USB settings in BIOS/UEFI menu. In both attempts, Simple Scan failed with error as shown in screenshot below.

I estimate 64-bit driver support is still lacking to this answered date. Or, 32-bit device driver must be used to make the scanner work properly. That being said, I even tried to install Simple Scan for 32-bit system on Xubuntu 14.04 64-bit system but failed miserably.
Now it works (2016-07-06)
I tested again Canon CanoScan LiDE 25 against Xubuntu 16.04 64-bit live system. I repeated the attempts above and it worked from both USB 2.0 and USB 3.0 ports. No further configuration is required; the scanner works out of box in 16.04 releases.
Above all, I didn't manage to figure out why it didn't work in 14.04 64-bit and why now it works for 16.04 64-bit. These LTS releases are already quite different in terms of kernel release, package version, program version, and others.
TL;DR For 64-bit system, the easiest solution is to use the current release (16.04). Else, the scanner works in 32-bit system of any release that is supported to this date.
