Scanner Frustration

[Jim Cornette]

Gerry Tool wrote:
> I have been trying to get my Epson 1240U scanner (which works in 
> everything prior to FC2Tx) to work, following bugzilla report 121511.  
> It is not clear exactly what needs to be done that seems to work for 
> some others.  Could someone post a complete step-by-step process to this 
> list that details how to get usb scanners to work in FC2T3?
> 
> Having a working scanner is a requirement for me to use FC2 when it is 
> released.
> 
> Thanks.
> 
> Gerry Tool
> 
> 
> 

 From the "Scanner Access Now Easy" website.


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.*

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" seems to work, 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.  SANE itsself comes with 
a hotplug script and related documentaion in the tools/hotplug/ 
directory. Please refer to the README in that directory for the details.


My comment:
Basically, permissions are not setup correctly with libusb. You need to 
set the permission of whatever device position that sane-find-scanner 
states. This has to run as root. The file permissions will not recognize 
the scanner as a normal user.

Then you have to do what was stated above. I just tried to open my 
scanner without changing the file permissions and it did not work. I 
then ran the below command as root.

chmod a+rw /proc/bus/usb/001/004

(001 is for the hub. 004 is the port on the hub, for my scanner. This 
gives the scanner file permissions rw for owner, group and others)

  ls -la /proc/bus/usb/001/004
-rw-rw-rw-  1 root root 57 May  3 18:13 /proc/bus/usb/001/004


I then tried the scanner as a regular user.  It worked after running
the command.

There is a new version that I just notified in the bug report mentioned 
above. Maybe the changes made will make scanner access easy again.

Hope this is clearer.