On 2017-07-18 17:19:08, Brian Potkin wrote: > On Mon 17 Jul 2017 at 20:56:48 -0400, Antoine Beaupre wrote: > >> Package: cups >> Version: 2.2.1-8 >> Severity: normal >> >> Hi! > > Hello Antoine. Thank you for your report. > >> When trying to share my printers with my roommates through the CUPS >> web interface, I quickly found the "Share printers connected to this >> system" button and clicked it. And lo and behold, other Linux (and >> probably Mac, haven't tried) computers just see the printers and can >> print to it. Great! > > What do you mean by "just see the printers"?
I mean that, when they choose the "Print..." menu in an application (e.g. Firefox or Evince), the printer shows up in the printer selection dialog. > My understanding would be that when you switch your server on, its > printers simply appear in the output of 'lpstat -a' (and in the > printing dialogs of applications) on client machines. I haven't tested the commandline version of this usage. I assume my users are not proficient with the commandline and like to use the GUI for things like printing... > This is achieved through the agency of cups-browsed and does not > involve the owners of these machines touching a single key on the > keyboard. If they have done, they are probably going about it in the > wrong way. Close down your server and the printers disappear from > 'lpstat -a'. Sure. The clients did not touch the keyboard: only the mouse. ;) >> But when they do, they get this mysterious error message: "Filter >> failed". Searching for that error message on the web is a dead end: >> you end up with all sorts of errors with foomatic-db not being >> configured properly and so on. This problem is remote-specific: >> printing works fine on the local machine, just not from the remote >> CUPS clients. > > We would need an error_log from a client to get to the bottom of this. > The Printing section on wiki will guide you on this. Please compress > the file before sending it to the bug. Understood, I'll see if i can find the time to send this. Actually, looking at the "Printing" page on the wiki: https://wiki.debian.org/Printing I do not see exactly what you are refering to. Or are you refering to this page: https://wiki.debian.org/DissectingandDebuggingtheCUPSPrintingSystem I must say the "Printing" page is a little confusing: there are too many links there and it's hard to figure out what's what. A "troubleshooting" section would be really helpful, for example. :) >> I have found this bug in the RedHat bugtracker that seems similar to >> the situation I'm seeing here: >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1010580 >> >> This is another forum with the simple solution: >> >> https://ubuntuforums.org/showthread.php?t=2254352 >> >> .. which is to run the following command, in a terminal: >> >> sudo lpadmin -p HP-LaserJet-p3015 -m raw >> >> where "HP-LaserJet-p3015" is the printer name. >> >> It seems to me a little odd that I would need to do this, as a user. I >> would expect the graphical interface to do the right thing, or just >> not offer the functionality at all. In the RH bugtracker, there's a >> debate regarding whether this is an actual bug, as this seems to be >> upstream's behavior of choice, but I fail to see how this is an >> appropriate response... I am using what are mostly default >> configurations here and didn't do anything special on the remote >> computer. > > cups-browsed does the right thing. The web interface does the right > thing too; a user who chose other than the raw "PPD" as an alternative > to using cups-browsed would be working against it. The user, AFAIK, did not make any specific choice on the printer configuration. >> It seems to me it would be essential to be able to share printers >> through the GUI in Debian, out of the box. Having people go through >> the commandline to workaround such an issue seems to defeat the whole >> point of having that GUI in the first place. >> >> Or did I miss something? > > The Printer section's account of "Double Filtering" on the wiki? :) I am not sure how I was expected to find this, but I did find this page after doing a full text search for the "double filtering" quoted string: https://wiki.debian.org/PrintQueuesCUPS#Double_Filtering Reading that section just makes me more confused - while I am sure I could spend the next 15 minutes trying to understand all the subtleties of the CUPS internals, I fail to see how users are expected to learn that stuff just to share printers over the network. I don't understand the trade-offs here: why isn't "raw" processing the default? What's the downside, if it allows automatic remote printing configurations? If I need to install cups-browsed on the client, why isn't that installed by default? It certainly seems to me that we expect way too much of our poor users. I've been using Debian for over a decade, and I've been a DD for years now, and I took my about 30 minutes to figure out how to make this work. I consider myself lucky that I find the magic incantation at all, and would be very surprised if a normal user would manage to fix this on their own. I guess one thing remains unclear to me: is remote printing automatic configuration supposed to work without commandline intervention right now? Or are we expected to switch the queue to raw mode on the server when we want to share printers? It seemed to me this was the issue here, but maybe that assumption is flawed... Thanks for the clarifications and responses! A. -- When spider webs unite, they can tie up a lion. - ethiopian proverb
