On Sun 18 Mar 2018 at 18:47:33 +0000, Brian Potkin wrote: > On Sun 18 Mar 2018 at 19:13:04 +0100, Jonas Smedegaard wrote: > > > Quoting Brian Potkin (2018-03-18 19:00:20) > > > During the management of bug #891810 this exchange took place between > > > Jonas Smedegaard and Didier 'OdyX' Raboud: > > > > > > Le dimanche, 4 mars 2018, 13.54:27 h CET Jonas Smedegaard a écrit : > > > > > Is PolicyKit _required_ for _all_ uses of hplip? > > > > > > > Good question. I'll admit I was put off my the (exhausting) 'systemd' > > > > argument, and hadn't checked what exactly was done with PolicyKit. > > > > > > > My reading is that PolicyKit is used to grant privilege to run > > > `hp-plugin` for > > > > plugin download, thereby avoiding the need for sudo. > > > > > > > So no, definitely not _required_. > > > > > > I thought that is the function of Policykit in hplip too so put it to > > > the test yesterday. stretch (base system only) was installed, upgraded > > > to unstable and then hplip (without its recommended packages) was > > > installed. 'hp-plugin -i' runs to completion after asking for and being > > > provided with the root/superuser password. There is no difference in the > > > outcome when policykit-1 is on the system. > > > > > > Maybe policykit-1 is used elsewhere with hplip (the GUI parts?) but I > > > did not look at this extensively. What I did do was use 'hp-setup -i' > > > without policykit-1 for a USB connected MFP. That gave > > > > > > error: No device selected/specified or that supports this functionality > > > > > > and journalctl indicated that permission to access the USB bus had been > > > denied. Easily solved (as it is when sane-find-scanner gives a negative > > > outcome) by installing libpam-systemd. (Or, interestingly, putting the > > > user in the scanner group). > > > > > > The small amount I did indicates that having policykit-1 as only a > > > Recommends: has not impacted unfavourably on the hplip package. > > > > Thanks for sharing those details. > > > > From what you quoted above, it seems that Didier already hinted that > > (likely) the need for systemd was "for plugin download". > > Note that neither of the two commands I used required policykit-1 to > be on the system for them to run successfully. What I forgot to mention > was that after installing libpam-systemd, the user has to log out and > log in again, so, as a non-expert guess, logind is involved somewhere. > > I am not arguing for changing the present arrangement wrt dependencies > but pointing out (assuming the testing is valid) that libpam-systemd > seems to be the more important package when hp-setup is used.
I do not have unlimited bandwidth but my ISP does not seem to have noticed I am well over my limit at the present. So what the hell - I installed hplip-gui to see whether it made a difference (not really expecting it to do) Sure enough, hp-plugin (as a user) downloaded and installed the plug-in. hp-setup gave error; No devices found on bus: usb No different from before. So what is the purpose of having policykit-1 installed (which it wasn't). -- Brian.
