Bug 696898 – net-print/cups: can't add USB-connected Zebra LP2844 except through file: URL

• Product: Gentoo Linux
• Status: RESOLVED DUPLICATE

[Description Scott Alfter 2019-10-07 15:11:54 UTC]

My understanding is that USB-connected printers should show up in CUPS so they can be added.  ISTR having a problem in the past getting an HP LaserJet 1320 talking to CUPS over USB (ended up adding a JetDirect); now, I'm trying to get a Zebra LP2844 label printer working.  It never shows up in the CUPS web interface when I go to add it.  /usr/libexec/cups/backend/usb reveals usb://Zebra/LP2844?serial=42A062401950 as the printer URL, but I can't send anything to it through this. 

I enabled CONFIG_USB_PRINTER in my kernel config and loaded usblp.  /dev/usb/lp0 now shows up, and if I point CUPS at file:///dev/usb/lp0 (and make another config change), I can print...but isn't this supposed to be deprecated?

I opened an issue with the CUPS people over here:

https://github.com/apple/cups/issues/5658

So far, we've found that the lp user isn't in the usb group, which keeps /usr/libexec/cups/backend/usb from working.  There's also an lpadmin group; lp isn't a member of that either.  Even with these changes, CUPS still won't detect the printer properly.

(I'm currently using CUPS 2.3.0, which is keyworded ~amd64, but I was having the same problems with CUPS 2.2.12.)

Reproducible: Always

Steps to Reproduce:
1. go to http://localhost:631/admin/
2. click "Add Printer"
3. new printer should appear in this list
Actual Results:  
The following are the only options that show up:

Local Printers:	 HP Printer (HPLIP)
Discovered Network Printers:	
Other Network Printers:	 Internet Printing Protocol (https)
 Internet Printing Protocol (ipps)
 Internet Printing Protocol (http)
 LPD/LPR Host or Printer
 Internet Printing Protocol (ipp)
 AppSocket/HP JetDirect
 Windows Printer via SAMBA
 Backend Error Handler

[Comment 1 Pacho Ramos 2021-08-18 07:16:32 UTC]

*** This bug has been marked as a duplicate of bug 644636 ***