Xorg guest session fails to start if the user has logged out and logged in again
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Light Display Manager |
Fix Released
|
High
|
Unassigned | ||
1.8 |
Fix Released
|
High
|
Unassigned | ||
lightdm (Ubuntu) |
Fix Released
|
High
|
Robert Ancell | ||
Saucy |
Won't Fix
|
High
|
Robert Ancell | ||
Trusty |
Fix Released
|
High
|
Robert Ancell |
Bug Description
[Impact]
Unable to switch sessions.
[Test Case]
1. Log in to the desktop.
2. Log out again. (But don't reboot or anything like that.)
3. Log in again.
4. Start a guest session.
Result: Depends on Xorg server in use. With intel driver, the guest Xorg session fails to start up with a DRM permission error (see attached Xorg.1.log). With virtualbox, and possibly AMD proprietary driver, the Xorg session on :1 appears to fight the one on :0 for control of the framebuffer - windows from both desktops get drawn over each other, causing a big mess.
The login/logout step is important: if you log in to the desktop immediately after the lightdm session has been started or restarted ("sudo service lightdm restart"), then the :1 session will start correctly.
(This problem can also be reproduced in another way: some desktops, when locking the display, create a new greeter instance on :1. This will also fail if the user has logged out and logged in again. For example, Xubuntu does this.)
[Regression Potential]
Low. Bug is a simple fix for wrong logic and has been running in Ubuntu 14.04 for some time without issue.
Related branches
- PS Jenkins bot: Approve (continuous-integration)
- Robert Ancell: Approve
-
Diff: 20 lines (+2/-2)1 file modifiedsrc/x-server-local.c (+2/-2)
description: | updated |
Changed in lightdm (Ubuntu): | |
importance: | Undecided → High |
Changed in xorg (Ubuntu): | |
importance: | Undecided → High |
Changed in xorg (Ubuntu): | |
status: | Confirmed → Invalid |
no longer affects: | xorg (Ubuntu) |
Changed in lightdm (Ubuntu Saucy): | |
status: | New → In Progress |
Changed in lightdm (Ubuntu Trusty): | |
status: | Confirmed → In Progress |
assignee: | nobody → Robert Ancell (robert-ancell) |
Changed in lightdm (Ubuntu Saucy): | |
importance: | Undecided → High |
assignee: | nobody → Robert Ancell (robert-ancell) |
Changed in lightdm: | |
importance: | Undecided → High |
Changed in lightdm: | |
milestone: | none → 1.9.4 |
status: | Fix Committed → Fix Released |
description: | updated |
Status changed to 'Confirmed' because the bug affects multiple users.