Public bug reported: SRU Justification:
[ Impact ] When the main tile in the topology is missing, and a user connects a tiled monitor, they will have a black / unusable screen on that monitor. This can occur in cases where a monitor has multiple physical connections, if a user connects to a port on the monitor that is not the main tile. [ Test Plan ] Scenario 1: User plugs in all related connections to the monitor with tiling capabilities to the same GPU. Scenario 2: User plugs into the port of the monitor that is the main tile. Scenario 3: User plugs into the port of the monitor that is not the main tile. Scenario 4: User plugs into the port of the monitor that is the main tile. [ Actual result ] Scenario 1: Tiling works as expected Scenario 2: Stretched content due to missing tiles, or monitor fails to light up (depends on monitor design) Scenario 3: No modeset, black screen Scenario 4: Stretched content due to missing tiles, or monitor fails to light up (depends on monitor design) (Note: Visualizations in upstream MP [0]) [ Expected result ] Content displays normally in all scenarios [ Fix ] This change treats the non-main tiled connection as though it is a normal monitor. In the situation where the connection only has tiled modes, the tiled mode would still be used. In the situation where normal modes are present and are preferred, those modes would be used instead. With this change, scenarios 3 and 4, illustrated above, change to display the content normally, while scenario 1 and 2 remain the same. [ Where problems could occur ] Users of tiled monitor configurations who might have adapted their setups to the unintended behavior in scenario 2 might need to re-adjust their resolution to accomodate the fixed behavior. There was also a function header change for meta_monitor_tiled_new - however, this is a private interface which should only be used internally by Mutter, and all other usages of it were adjusted accordingly. [ Other notes ] You will need a tiled monitor and will need to test a couple difference configurations with such a monitor as described in the MR. Ex: - Apple Studio Display - Dell UP2715K - Dell UP3218K - LG 27MD5KL [0] Upstream MP: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4685#c6052df6a0710d9892c9563092055a9b01b90516 ** Affects: mutter (Ubuntu) Importance: Medium Assignee: Mitchell Augustin (mitchellaugustin) Status: New ** Affects: mutter (Ubuntu Noble) Importance: Undecided Status: New ** Affects: mutter (Ubuntu Plucky) Importance: Undecided Status: New ** Affects: mutter (Ubuntu Questing) Importance: Undecided Status: New ** Affects: mutter (Ubuntu Resolute) Importance: Medium Assignee: Mitchell Augustin (mitchellaugustin) Status: New ** Changed in: mutter (Ubuntu) Importance: Undecided => Medium ** Changed in: mutter (Ubuntu) Assignee: (unassigned) => Mitchell Augustin (mitchellaugustin) ** Also affects: mutter (Ubuntu Noble) Importance: Undecided Status: New ** Also affects: mutter (Ubuntu Questing) Importance: Undecided Status: New ** Also affects: mutter (Ubuntu Plucky) Importance: Undecided Status: New ** Also affects: mutter (Ubuntu Resolute) Importance: Medium Assignee: Mitchell Augustin (mitchellaugustin) Status: New -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/2131575 Title: SRU backends/monitor-manager: Improve tiled monitor handling To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2131575/+subscriptions -- desktop-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
