USB printer configures up as /dev/usblp0 but should be /dev/usb/lp0 #818

michaelrsweet opened this Issue Jul 18, 2004 · 3 comments


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michaelrsweet commented Jul 18, 2004

Version: 1.1.21rc1 User: cbm.sfu

I run Gentoo ~x86. Recently upgraded to 1.1.21rc1 from 1.1.20. Using the web interface to setup my printer (an epson c42ux) resulted in DeviceURI of usb:/dev/usblp0. However, my system only has /dev/usb/lp0.

I'm using DEVFS. Perhaps /dev/usblp0 is correct for udev or something like that?

(don't think it matters but I'm running the gimp-print drivers 4.2.6)


michaelrsweet commented Jul 19, 2004 User: kmuto.debian

This is a fallback problem.
When CUPS failed to detect USB device (it happens when user uses udev
or devfs), CUPS uses /dev/usblp0 as default. /dev/usblp0 is invalid
for many FHS compatible Linux distributions.

Here is a patch.

--- backend/usb-unix.c.old 2004-07-13 20:39:39.000000000 -0400
+++ backend/usb-unix.c 2004-07-14 08:51:49.000000000 -0400
@@ -426,12 +426,12 @@

  • First figure out which USB printer filename to use...
  • if (access("/dev/usb/lp0", 0) == 0)
  • strcpy(format, "/dev/usb/lp%d");
  • if (access("/dev/usblp0", 0) == 0)
  • strcpy(format, "/dev/usblp%d");
    else if (access("/dev/usb/usblp0", 0) == 0)
    strcpy(format, "/dev/usb/usblp%d");
  • strcpy(format, "/dev/usblp%d");
  • strcpy(format, "/dev/usb/lp%d");


  • Then open each USB device...

michaelrsweet commented Aug 2, 2004 User: mike

Applied kmuto's patch (there were actually two places this needed to happen) for 1.1.21rc2.



michaelrsweet commented Aug 2, 2004 User: mike

Fixed in CVS - the anonymous CVS repository will be updated at midnight EST.

michaelrsweet added this to the Stable milestone Mar 17, 2016

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