[SOLVED] xsane does not find scanner and libusb permission error

H_TeXMeX_H · 10-25-2010, 02:22 PM

I am tired, and I simply can't find an easy answer.

So, today I need the scanner in slackware64 13.1, only to find that it does not work as user. I have an HP Deskjet F2180 and using CUPS it is identified as hp:/usb/Deskjet_F2100_series?serial=CN81H4S2SP04TK.

In the past the simple solution was to add oneself to the right groups, but it does not work this time.

As user I get:

Code:

bash-4.1$ sane-find-scanner 
...
  # No SCSI scanners found. If you expected something different, make sure that
  # you have loaded a kernel SCSI driver for your SCSI adapter.

libusb couldn't open USB device /dev/bus/usb/001/001: Permission denied.
libusb requires write access to USB device nodes.
libusb couldn't open USB device /dev/bus/usb/001/001: Permission denied.
libusb requires write access to USB device nodes.
libusb couldn't open USB device /dev/bus/usb/002/001: Permission denied.
libusb requires write access to USB device nodes.
libusb couldn't open USB device /dev/bus/usb/002/001: Permission denied.
libusb requires write access to USB device nodes.
...
libusb couldn't open USB device /dev/bus/usb/008/001: Permission denied.
libusb requires write access to USB device nodes.

As root:

Code:

bash-4.1# sane-find-scanner 
...
found USB scanner (vendor=0x03f0 [HP], product=0x7d04 [Deskjet F2100 series]) at libusb:005:003
  ...

I can confirm scanning works as root, I tried it.

Now, for the strange part:

Code:

bash-4.1$ groups
users floppy audio video cdrom plugdev power netdev scanner

I can confirm that I belong to all these groups. Strangely tho, I ran groups earlier today with same output, then checked '/etc/groups' to find that I was actually not in the scanner group. I added myself and rebooted, it did not work.

Thanks for any help.

Oh, I do have a custom kernel, will post the config if you need it. I started with the slackware generic config, so it's not that far from the slackware kernel.

EDIT: Printing works fine.

markush · 10-25-2010, 03:29 PM

Hello H_TeXMeX_H,

I'm running a HP Deskjet 1410 Printer/Scanner. I always ad the users to the lp group since this is necessary to get permissions to access the device. Without beeing member of lp one can print with cups but has no access to the scanner.
But this has nothing to do with your issue that root cannot find the scanner with the find-scanner command.
Afaik one has to configure the kernel for an usb-scanner. But I'm not sure where to find this.

Markus

H_TeXMeX_H · 10-26-2010, 03:35 AM

Thank you very much, you have solved it. All I did extra was:

Code:

usermod -a -G lp demonslayer

So now I get:

Code:

bash-4.1$ groups
users lp floppy audio video cdrom plugdev power netdev scanner

Also, the scanner was being detected as root, those comments are messy, that's all, here I've fixed it.

EDIT: I hope Alien Bob sees this, so that 'lp' will be one of the default extra groups.