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Login Screen Over Wayland

Summary

Change the Login screen that GDM uses to run on Wayland instead of X.

Owner

  • Name: Ray Strode
  • Email: rstrode@redhat.com
  • Release notes owner:

Current status

This mostly in place now. GDM starts the login screen on wayland, but will fallback to Xorg if wayland doesn't work.

Detailed Description

At the moment, a user can choose to log in to a Wayland session from the login screen, but the login screen itself always runs on top of X. The point of this change is to change that, and make the login screen always run on a Wayland session.

Benefit to Fedora

Fedora is steadily progressing toward the goal of replacing X uses with Wayland based uses instead. This is one step toward achieving that goal. The login session is sufficiently isolated and contained, that it makes an ideal first place to put Wayland by default. There should be little to no user visible impact with this change. Ideally the user won't be able to tell the difference between the login screen running on X versus the login screen running on Wayland.

Scope

  • Proposal owners: The main things that need be accomplished are:
    • Change GDM to not start an X server at startup, instead run the login screen in Wayland mode
    • Change X based user sessions to run on their own VT, since they can no longer piggyback off the login screen VT
    • Come up with some answer for proprietary Nvidia driver users, since that stack doesn't yet support Wayland. One idea is to force the login session to fallback to using X.
  • Other developers: We may need to get the mesa maintainer involved as part of a proprietary Nvidia driver handling, but also might not need to pending investigation.
  • Release engineering: This change doesn't affect release workflow
  • Policies and guidelines: This change doesn't affect packaging guidelines

Upgrade/compatibility impact

Shouldn't impact upgrades

How To Test

  1. Boot machine
  2. Ensure graphical login screen comes up
  3. Jump to VT 6 and log in at console
  4. Run "ps -ef | grep Xorg" and ensure Xorg isn't running
  5. Return to VT 1
  6. Try to log into a "GNOME" session
  7. Log out
  8. Try to log into a "GNOME Wayland" session
  9. Log out

Steps 5 through 8 make sure that login screen is still able to log into user sessions.

User Experience

Should not have a noticeable impact in user experience

Dependencies

Might require changes to mesa packaging, but that's not known for sure yet.

Contingency Plan

  • Contingency mechanism: Revert to existing mechanism of login screen on Xorg
  • Contingency deadline: Beta Freeze
  • Blocks release? No
  • Blocks product? No

Documentation

No upstream documentation or bug links yet

Release Notes

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