as root on two different consoles. It doesn't take long for them to start alternate showing and not showing the printer and if you are unlucky the printer will suddenly disappear and not come back until it is unplugged and replugged in.
I'm guessing this is either a hardware fault or that that the kernel USB driver on my system is a little bit flakey.
OK after a lot effort I have narrowed this down a bit. I can show the same problem using:
watch -d=cumulative --interval=0.5 /usr/lib/ cups/backend/ usb
as root on two different consoles. It doesn't take long for them to start alternate showing and not showing the printer and if you are unlucky the printer will suddenly disappear and not come back until it is unplugged and replugged in.
I'm guessing this is either a hardware fault or that that the kernel USB driver on my system is a little bit flakey.