On Tue 02 Jan 2018 at 10:13:01 +0100, Helmut Grohne wrote: > On Mon, Jan 01, 2018 at 03:47:04PM +0000, Brian Potkin wrote: > > evince can get remote printer information from cups-browsed but, if the > > latter is not running, it browses the Bonjour broadcasts of servers and > > printers directly, just as avahi-browse does. > > I cannot confirm the described behaviour.
The print dialog is empty when cups-browsed is stopped? Mystifying! GTK+ uses the avahi library to list printers and print queues advertised by the DNS-SD protocol. https://bugzilla.gnome.org/show_bug.cgi?id=688956 You have attained a goal others have striven for. :) https://lists.debian.org/debian-user/2017/09/msg00980.html > > > > First things first. Are you still experiencing this behaviour on an > > > > up-to-date unstable/testing system? > > > > > > Yes. I see this behaviour on stretch and sid. > > > > I am working with sid. Are you using AppArmor on Stretch? > > I have never explicitly enabled AppArmor. The stretch system is pretty > close to a standard installation. I haven't fiddled with it much. Just ruling out AppArmor. It would have to be explicitly installed on stretch.... > The sid system certainly isn't using AppArmor and could have a few > oddities: It was installed as potato and upgraded since. ...but not on unstable as it is a Recommends: of linux-image. > > Let's see whether cups-browsed has any connection with the issue. Stop > > it running and bring up evince. Its print dialog should show the remote > > printers it gets from mdns broadcasts. You relate the printers disappear > > a few times a day, so we shouldn't have to wait too long to see whether > > it happens in this situation. BTW, is there any discernable pattern to > > the behaviour? Time of day, time interval etc? > > As soon as I stop cups-browsed, all printers disappear. The ppd files > are deleted. lpstat does not know them anymore and they disappear from > the evince print dialog (or don't show up there if I restart evince). > When cups-browsed is started again, the printers in evince, the ppd > files and the lpstat output is back again pretty much immediately. > > Concerning the timing, I looked hard before filing the bug report. Log > rotation was something obvious to correlate it to, but without luck. The > waiting time seems exponentially distributed to me. Sometimes I had it > multiple times within an hour other times a day went by without. I hate it when events are random. > When I ran the whole thing under strace, it didn't happen within 12h. > > > Thanks for the offer. Have a good look at what journalctl says. Search > > for clues with "avahi", "audit", SIGTERM (and anything else you can > > think of). > > I checked that much before the filing. I'm afraid we'll need to turn on > some more logging to get useful things here. Just what should I enable? > The manual page of avahi-daemon.conf is pretty scarce on debugging > options. cups-browsed logging is pretty much off by default and when you > enable it you only see the fact that printers get removed, not why. You appear to have exhausted all the options I would suggest. > You see, this issue is not easy to debug. I hope you can bear with me. My interest in this bug arises from its affecting cups-daemon and my knowledge of avahi is not great. It seems avahi-daemon stops providing cups-browsed with information and the printer list would disappear, of course. I would have been interesting to find out if the same thing happens with the GTK dialog. Cheers, Brian. > > Helmut