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Bug 1896265 - Mutter 3.38 fails to detect tiled displays correctly (treats each half as separate display)
Summary: Mutter 3.38 fails to detect tiled displays correctly (treats each half as sep...
Alias: None
Product: Fedora
Classification: Fedora
Component: mutter
Version: 33
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
Assignee: Florian Müllner
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2020-11-10 08:11 UTC by cyshei
Modified: 2020-11-19 01:29 UTC (History)
6 users (show)

Fixed In Version: mutter-3.38.1-2.fc33
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Last Closed: 2020-11-19 01:29:28 UTC
Type: Bug

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
GNOME Gitlab GNOME mutter issues 1524 0 None None None 2020-11-10 08:11:01 UTC

Description cyshei 2020-11-10 08:11:01 UTC
Description of problem: Some displays such as the Dell UP2414Q and LG UltraFine 5K use one DisplayPort connection for each half of the display and expose this in the TILE EDID property.  Mutter is supposed to parse this info and merge the two halves back into a single display, but version 3.38 reversed an if condition and broke this functionality.

Version-Release number of selected component (if applicable): 3.38.1

How reproducible: 100%

Steps to Reproduce:
1. Connect tiled display and launch GNOME

Actual results: Display should appear as single monitor in settings

Expected results: Each half of the display is treated as a separate monitor

Additional info: This has already been fixed upstream and is a 1-character patch to reverse the if condition so it works as intended (link to bug attached).

Could this fix be temporarily applied as a patch to the Fedora package until it's presumably fixed in Mutter 3.38.2?  Unfortunately, I have both the Dell UP2414Q and LG UltraFine 5K monitors, so GNOME is pretty broken for me on F33 right now, and I'm using i3 as a workaround for now.  Thanks!

Comment 1 Jonas Ådahl 2020-11-10 09:10:45 UTC
Yes, it'll be fixed in 3.38.2.

Comment 2 Jonas Ådahl 2020-11-10 09:12:11 UTC
Backporting is indeed an option if 3.38.2 isn't to be released yet, I'll check.

Comment 3 Fedora Update System 2020-11-17 14:04:25 UTC
FEDORA-2020-543204d787 has been submitted as an update to Fedora 33.

Comment 4 Fedora Update System 2020-11-18 01:08:46 UTC
FEDORA-2020-543204d787 has been pushed to the Fedora 33 testing repository.
In short time you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --advisory=FEDORA-2020-543204d787`
You can provide feedback for this update here:

See also for more information on how to test updates.

Comment 5 Fedora Update System 2020-11-19 01:29:28 UTC
FEDORA-2020-543204d787 has been pushed to the Fedora 33 stable repository.
If problem still persists, please make note of it in this bug report.

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