well, anyway,
LONG version of 1st post,
Hi, I love Mint and Cinnamon, I recently found a fix for several problems I had, and I'm here to share the fix (or workaround) with comrades. Finding the cause took a lot of time, and even after it, I searched extensively and can confirm that, apparently, this problem is not documented. It took me 2 days to find exactly how to reproduce this, and try to understand what was happening, and read documentation on cinnamon and the polkit agent, and github issues, and produce good logs, etc. I'm here to share my findings. (and ask comrades if this was fixed since Mint 19.1 (my version) / Cinnamon 4.0.10)
For several months I've had problems with,
- flatpak applications disappearing from Mint menu, after some time...
- Mintinstall unable to install some programs (even non flatpak)
There were workarounds, but the other day I tried to launch ufw (firewall) from Mint Menu. This actually calls gufw, the GUI version. I hit enter or clicked "ufw", and everything froze suddenly. Couldn't restart Cinnamon with Ctrl+Alt + Esc. Couldn't Alt+F2, nothing.
Long story short, I found all these problems are related, and happen after I restart Cinnamon from another TTY, e.g. TTY1.
On my machine, I can confirm that ALL the flavors of "... DISPLAY=:0 ..." cause the problem.
Code: Select all
$ export DISPLAY=:0; cinnamon --replace
$ DISPLAY=:0 cinnamon --replace
$ cinnamon --replace --display=:0
and other flavours like DISPLAY=:0 cinnamon-launcher
The commands with "export" cause the worst freezes when trying to launch an application requiring elevated priviledges from Mint Menu. With the mere "DISPLAY=:0" I could go back to TTY1 and understand the problem : the polkit-gnome-authentication-agent does ask for password, but only in the TTY where cinnamon was started. But authenticating is impossible. My name being LOFI, the polkit agent asks the password for "LOFI,,," (three commas added, can't be removed). But even if polkit authentication from TTY was possible, that would be quite a broken user interface ! I noticed that as soon as I click "ufw", a stop signal is sent to cinnamon (status : T). A workaround is to send a SIGCONT to cinnamon, but the polkit problem remains.
What's weird is that auth.log doesn't show a prompt to authentify "LOFI,,," but this,
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[timestamp] [my-computer-name] polkitd(authority=local): Registered Authentication Agent for unix-process:5822:91784 (system bus name :1.90 [pkexec gufw-pkexec LOFI], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8)
(locale is incorrect)
With flatpak, at least you don't get freezes, as the programs completely disappear from the menu. (they can be launched with flatpak run). As for Mintinstall, you click "install", you often are warned that "several additional packages are required", "ok", then the installation stops without an explanation. I used to think there was a dependency problem, I would try apt from command line, and would be surprised that it worked, for mysterious reasons.
Strangely, the polkit agent problem (when cinnamon was restarted from another TTY) doesn't affect mintupdate.
I found that, for example, polkit rules for flatpak is to allow members of the sudo group. Without the authentication agent, Cinnamon can't run a flatpak program.
I wanted to find a real fix, but I couldn't. Some people say that from TTY1, you are root. I found this is not the case on my configuration. Thanks to the top monitoring command (tree view) I saw that cinnamon or cinnamon --launcher is normally a subprocess of mint-session. With the commands above (display 0 cinnamon --replace),
cinnamon becomes a subprocess of (in my case) : init / login -p -- / zsh.
Instead of :
init / lightdm / lightdm --session-child / cinnamon-session (polkit-gnome-authentication-agent being on the same level).
The different flavours of DISPLAY=:0 cinnamon commands are widely recommended online, for example in major askubuntu threads. That's why in 2015 Bernd Wechner started a thread here (about cinnamon) and created an issue on github that got quite big.
https://github.com/linuxmint/cinnamon/issues/4763 "no clear way to restart cinnamon from TTY"
His point was that sometimes, there's no other way to restart cinnamon than to open another TTY. But the command is not reliable. (but polkit problems were not mentioned) (issue is closed)
Is there a way to restart cinnamon from TTY1 and make sure that it becomes a subprocess of mint-session? How? I've looked into Python subprocesses and searched stack exchange...
https://unix.stackexchange.com/question ... ferent-tty I see ideas, but that don't look too good, so much that I didn't try them.
So *if* this is still a problem in Mint 20 and 21,
the "workaround" that I propose, when Cinnamon freezes and you can't open a terminal, and Ctrl+Alt + Escape doesn't work, is to restart cinnamon from TTY, save your work, log out and log back in.
Though it would be nice to have a command to restart cinnamon without breaking the link with the polkit agent (maybe restart it from TTY too ??), I'm not doing a feature request. My main point is I worry for less experienced comrades. Unless it was fixed since Mint 19.1, many users must find online, after a hard freeze, the protip to restart Cinnamon from TTY. Then they copy/paste the command, and then they have no way to understand why some programs disappeared, and they can also run into hard freezes, just for trying to open an app that requires elevated priviledges from the Menu.
So I hope that with this post, if confirmed, search engines will bring people here, and they will find that several of their problems are caused by the fact that their running version of cinnamon was started incorrectly.
Else I don't know, from a scale from easy to impossible, how hard it would be for the devs to change cinnamon so that it would detect when it's run from a text TTY, and would ask the user what it is exactly that they want to do ? Anyway, this is not a feature request from my part. This would not be the place anyway, I'd make it on github. I love Mint Cinnamon and I just wanted to share this, and find a way to spare as many comrades as possible from spending hours on it like I did.
best regards
lofi
Dunno if I mentioned it already, but you should head on over to GitHub with this, because this is the sort of stuff the developers need to see, although they may already be aware of and working on this. If you're comfortable making a GitHub account, of course. It's a bit stupid you need an account to post a bug report on GitHub, TBH.