Re: hp-plugin and hp-setup with 3.17.20+repack0-5
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.
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