Ensure wayland -> xorg fallback to the corresponding session
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
gdm |
Fix Released
|
Medium
|
|||
gdm3 (Ubuntu) |
Fix Released
|
High
|
Olivier Tilloy | ||
Artful |
Fix Released
|
High
|
Olivier Tilloy | ||
gnome-session (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
[Impact]
Users upgrading to artful on a system that cannot run wayland may be logged into an unexpected session at the next boot.
[Steps to reproduce]
1. On a system with wayland capability, log into the "Ubuntu" session.
2. Install gnome-session if it wasn't already installed (this adds two sessions, "GNOME" and "GNOME on Xorg").
3. Disable wayland (uncomment WaylandEnable=false in /etc/gdm3/
Expected result: at the greeter, the "Ubuntu on Xorg" session is selected by default (falling back from "Ubuntu" to "Ubuntu on Xorg").
Actual result: at the greeter, the "GNOME on Xorg" session is selected by default.
[Fix]
The fix consists in using the default fallback mechanism in gdm3, i.e. /usr/share/
The fix involves a distro-patch in gdm3 (already merged upstream, will go away with the next release) and changes to the packaging of gnome-session (added symlinks).
[Test Case]
see [Steps to reproduce]
[Regression Potential]
The gdm3 patch has been thoroughly tested and merged upstream. Since this is C glib code, reviewers should carefully look for possible memory leaks, as strings are being allocated.
If a package installs /usr/share/
In case of a partial upgrade:
- only gdm3 upgraded: nothing user-visible should happen, as gdm will ignore the foo-xorg session only if the corresponding foo session file exists
- only gnome-session upgraded: with wayland disabled, at the greeter the user might see two sessions that are in fact the same thing: "Ubuntu" and "Ubuntu on Xorg" (but logging into any of the two will work)
One minor gotcha with this patch: if, with wayland enabled, one intentionally selects ubuntu-xorg, then disables wayland, then reboots, in the login screen no session is selected in the dropdown (because gdm ignored ubuntu-xorg). However this will still launch the ubuntu-xorg session by default (which effectively is the same as the ubuntu session), so all is good (except for the fact that no session appears selected in the dropdown). This has the advantage of retaining the "ubuntu-xorg" session selected by the user if wayland is re-enabled later, though.
This is a regression in the sense that no session is visually selected in the dropdown, but it doesn't affect the default session selection.
Related branches
- Sebastien Bacher: Approve
- Didier Roche-Tolomelli: Approve
-
Diff: 29 lines (+12/-0)3 files modifieddebian/changelog (+10/-0)
debian/gnome-session.links (+1/-0)
debian/ubuntu-session.links (+1/-0)
- Sebastien Bacher: Approve
- Didier Roche-Tolomelli: Approve
-
Diff: 74 lines (+54/-0)3 files modifieddebian/changelog (+9/-0)
debian/patches/series (+1/-0)
debian/patches/ubuntu_ignore_sessions_xorg_suffix.patch (+44/-0)
tags: | added: rls-aa-incoming |
summary: |
- Ensure wayland -> xorg fallabck to the corresponding session + Ensure wayland -> xorg fallback to the corresponding session |
Changed in gdm3 (Ubuntu): | |
assignee: | nobody → Olivier Tilloy (osomon) |
importance: | Undecided → High |
Changed in gdm3 (Ubuntu): | |
status: | Confirmed → In Progress |
Changed in gdm: | |
importance: | Unknown → Medium |
status: | Unknown → Confirmed |
Changed in gdm: | |
status: | Confirmed → Fix Released |
description: | updated |
Changed in gdm3 (Ubuntu): | |
status: | In Progress → Fix Committed |
We don't want to commit to fixing this in time for release. It would be nice to fix, but not a release blocker.