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Potomac

Member

Registered: 2011-12-25

Posts: 529

[solved] "/dev/usb/lp1" is used instead of "/dev/usb/lp0" for printers

I notice a weird thing :

- since a recent "pacman -Syu" ( maybe the kernel or systemd package ) my canon USB printer LBP3000 is assigned to /dev/usb/lp1 instead of /dev/usb/lp0,

this change triggers a problem with my cups configuration, because my printer was configured with /dev/usb/lp0,

the solution was to do this command :

ccpdadmin -p LBP3000 -o /dev/usb/lp1

I want to know why kernel/systemd uses the path "/dev/usb/lp1" instead of "/dev/usb/lp0" even when only one printer is used ? ( I don't have a second USB printer )

Last edited by Potomac (2015-11-03 20:03:27)

Potomac

Member

Registered: 2011-12-25

Posts: 529

Re: [solved] "/dev/usb/lp1" is used instead of "/dev/usb/lp0" for printers

I found the answer,

this change was triggered by my battery backup device (MGE UPS PROTECTION CENTER 645 ), if I disconnect this device(  by removing the USB cable ) then the bug is gone, the path "/dev/usb/lp0" is used for my USB printer,

inside this battery backup device there is an usb to parallel port device in it, which probably triggers a different order in /dev/usb for lp* devices when the kernel detects my battery backup device "MGE UPS"

ukhippo

Member

From: Non-paged pool

Registered: 2014-02-21

Posts: 366

Re: [solved] "/dev/usb/lp1" is used instead of "/dev/usb/lp0" for printers

I don't have a USB printer to try this, but perhaps use a udev rule to create an alias for whichever lpX the kernel assigns your printer. Use the alias for cups.

Potomac

Member

Registered: 2011-12-25

Posts: 529

Re: [solved] "/dev/usb/lp1" is used instead of "/dev/usb/lp0" for printers

yes I created an udev rule in order to solve this problem :

SUBSYSTEMS=="usb", ATTRS{idVendor}=="04a9", ATTRS{idProduct}=="266a", ATTRS{serial}=="0000A1551Krc", SYMLINK+="usb/lbp3000"

a symlink will be created : /dev/usb/lbp3000 and I use this symlink for the configuration of ccpdadmin :

ccpdadmin -p LBP3000 -o /dev/usb/lbp3000

Last edited by Potomac (2015-11-03 20:02:34)