Bug#979177: cups-filters-core-drivers: Adding a printer impossible because "driverless" is too slow

[Brian Potkin <claremont102@gmail.com>]

tags 979177 moreinfo
thanks


On Sun 03 Jan 2021 at 23:24:10 +0200, Shai Berger wrote:

> Package: cups-filters-core-drivers
> Version: 1.28.6-1
> Severity: normal
> 
> Dear Maintainer,
> 
> I've seen some misbehavior from my printer, and tried to remove and add it
> back again. This failed, with the symptoms described in
> https://unix.stackexchange.com/questions/276736/cups-adding-printer-fails-with-unable-to-get-list-of-printer-drivers-success
> that is, no matter what interface I use -- KDE, Gnome or the web
> via localhost:631 -- I get the same error when trying to find
> drivers for the printer:
> 
> 	Unable to get list of printer drivers:
> 	Success
> 
> Following the advice on that page, I tried to see if removal of
> one of the files in /usr/lib/cups/driver can help me get faster
> results, and I found that the guilty script was
> /usr/lib/cups/driver/driverless

Thank you for your report, Shai.

How do you go on with 'lpinfo -m' when
  * /usr/lib/cups/driver/ contents are as normal?
  * /usr/lib/cups/driver/ contains only driverless?
 
> I then tried to run this script in isolation, and got:
> 
> $ time /usr/lib/cups/driver/disabl/driverless list
> DEBUG: Started ippfind (PID 19070)
> Failed to get info about driverless support.
> "driverless:ipp://HP%20OfficeJet%206950%20%5B00A23E%5D%20(USB)._ipp._tcp.local/" en "HP" "HP OfficeJet 6950, driverless - cannot check driverless status, cups-filters 1.28.6" "MFG:HP;MDL:OfficeJet 6950;CMD:PCLM,PCL,PWGRaster,AppleRaster,JPEG,URF,PWG;"
> "driverless-fax:ipp://HP%20OfficeJet%206950%20%5B00A23E%5D%20(USB)._ipp._tcp.local/" en "HP" "HP OfficeJet 6950, Fax, driverless - cannot check driverless status, cups-filters 1.28.6" "MFG:HP;MDL:OfficeJet 6950;CMD:PCLM,PCL,PWGRaster,AppleRaster,JPEG,URF,PWG;"
> DEBUG: ippfind (PID 19070) exited with no errors.
> 
> real    3m1.817s
> user    0m0.005s
> sys     0m0.015s

I get a similar real time and output to you but without "Failed to get
info about driverless support." and "cannot check driverless status,".
It would seem your device failed to respond to any requests for the IPP
versions available. This is a check for which type of driverless support
is available. The absence of the information does not appear to be a
show stopper as a URI (ipp://...) is still obtained.

> Noticing my specific printer named in the output -- could it be
> that the script tries to communicate with it, but fails to do it
> in a robust way?

It doesn't look like it. The driverless output seems reasonable to me.

Please give the outputs of

  systemctl list-units "ipp-usb*" | grep service

and

  lpstat -t

Regards,

Brian.