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Bug 1896265

Summary: Mutter 3.38 fails to detect tiled displays correctly (treats each half as separate display)
Product: [Fedora] Fedora Reporter: cyshei
Component: mutterAssignee: Florian Müllner <fmuellner>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 33CC: fmuellner, gnome-sig, jadahl, otaylor, philip.wyett, walters
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: mutter-3.38.1-2.fc33 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-11-19 01:29:28 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

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. https://bodhi.fedoraproject.org/updates/FEDORA-2020-543204d787
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: https://bodhi.fedoraproject.org/updates/FEDORA-2020-543204d787

See also https://fedoraproject.org/wiki/QA:Updates_Testing 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.