installer: autorun xserver in graphical media

[worldofpeace]

Motivation for this change

When I first used the NixOS iso I found it confusing and strange to have to do systemctl start display-manager. I assumed that I would have went straight to the graphical environment.

If anyone has a reason as to why it shouldn't do this please share.

Notes

In #42610 @adisbladis suggested:

I think we should add another boot entry so you can still choose not to start the graphical environment, at the same time we make the one that autostarts the graphical environment the default.

Wouldn't this need #45345 to include that configuration as a child config in the grub menu?

Though I feel that might be to complex.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Fits CONTRIBUTING.md.

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cc @samueldr @xeji @grahamc

[samueldr]

I would like to know why it wasn't the default. There is probably a reason behind, and knowing it helps ensuring we don't cause any unintended issues.

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Though, I think this requires the one important sub-feature: the installer media should present an option that disables the display-manager.service so one can use the graphical iso without having X started; in case starting X is causing issues. IIRC this can be done through a systemd.mask=display-manager.service option on the kernel command line.

[worldofpeace]

I would like to know why it wasn't the default. There is probably a reason behind, and knowing it helps ensuring we don't cause any unintended issues.

It seems it was a while ago

nixpkgs/modules/profiles/graphical.nix

Line 12 in f3cc01b

autorun = true;

Though, I think this requires the one important sub-feature: the installer media should present an option that disables the display-manager.service so one can use the graphical iso without having X started; in case starting X is causing issues

Was this perceived as a necessary addendum to the feature suggested by @adisbladis?
If so, could you justify the importance?

[samueldr]

Yes, sorry, bad habit, jumped the gun and added my thoughts before reading that this was already in the body of your PR.

This is one way the boot option can be implemented.

[worldofpeace]

No problem, I'm guilty of the same thing too when I'm busy.

[worldofpeace]

If there's an agreement to needing this feature implicitly then I'd say that this is blocked until
the tests for #45345 are reviewed and it's merged.

[samueldr]

Unless I'm misunderstanding, probably no relation. The installer iso has a different menu generation entirely from the installed system.

Around here a new option can be added (class is used to get an icon in the menu).

[mmahut]

Any updates on this pull request, please?

[worldofpeace]

I plan to pick this up again after the 19.09 release.

[worldofpeace]

Ok, rebased and added a quirk to disable the display-manager.
I think we might've discussed on having a way to condition menu entries on whether it's for the graphical media or minimal. Though I still think this change won't do much harm without that feature.

[worldofpeace]

I've tested running the graphical media

• Does it autorun X starting plasma5 ✔️
• Did enabling the quirk send me to the tty ✔️

[samueldr]

We can introduce an icon, if desired, and if one can be composed. They are composed from the breeze icon theme. If you see something in it that can be adapted, or used as an inspiration I can look into adding it to the relevant artwork.

[worldofpeace]

I found breeze/devices/64/video-display.svg the most suitable.
I mostly wanted something like just a blank monitor, or communicates a tty.

[worldofpeace]

I'm highly partial to elementary's icons which appears to be exactly what I'm looking for

[samueldr]

Oh, forgot to specify the symbolic icons. Though the one from breeze, once made into outlines, may work, I'll try to remember to look into it later. (The PR can be merged without that change.)

[worldofpeace]

Ahh, there's computer/video-display symbolic icons that should be fine then.
I'll add an issue at nixos-artwork for that once merged @samueldr.

[samueldr]

Minor stuff, generally approving the change.

[worldofpeace]

@samueldr My English and personality is literally a neologism 🤣

Thanks for the suggestions, will try to implement.

[worldofpeace]

Rebased and resolved the conflicts in the release note.
I plan to integrate this some time today if there's no issues raised.