https://bugs.kde.org/show_bug.cgi?id=526072
Bug ID: 526072
Summary: DisplayPort output stops streaming after DPMS wake
(5120x2160@180); regression in 6.7.5, fine in 6.7.4
Classification: Plasma
Product: kwin
Version First unspecified
Reported In:
Platform: Other
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: multi-screen
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 196439
--> https://bugs.kde.org/attachment.cgi?id=196439&action=edit
System info from the affected machine: kernel dmesg (section 1) and
kscreen-doctor output (section 2). Disk UUIDs and MAC address redacted.
System:
- KWin Wayland, Plasma 6.7.5, Fedora Atomic (Bazzite), kernel 7.2.4
- NVIDIA proprietary 610.57.04, RTX PRO 6000 Blackwell
- Monitors: center 5120x2160@180 Hz via DisplayPort (DP-5), two side displays
3440x1440 via DisplayPort
Steps to reproduce:
1. Let the displays enter DPMS sleep (or force it: kscreen-doctor dpms.off),
then wake.
Observed:
- Center output reconnects as enabled + connected with the correct mode
selected. kscreen-doctor reports no problem.
- Monitor shows no signal. The link is not streaming.
- kscreen-doctor dpms.on does not restore it.
- Forcing a retrain (output.DP-5.disable, 3 s, enable) restores it only
sometimes on a settled session. It failed while the compositor was loaded
(journal showed "compositor not processing events fast enough"), and one such
attempt took all three displays dark for roughly 90 s. The two side displays
recovered. The 5K stayed dark until reboot.
- A reboot always restores it.
Expected:
- Output resumes streaming on DPMS wake.
Frequency:
- Occurred on every sleep/wake cycle tested on 6.7.5. Side displays were
unaffected.
Regression window:
- Same machine, same kernel, same driver, same cables and monitors, image
rolled back with rpm-ostree:
Plasma 6.7.4 (image 44.20260908): sleep/wake works.
Plasma 6.7.5 (image 44.20260916): fails as above.
- Searched Bugzilla and forums for this signature (5K DP no signal after sleep,
reports connected+enabled, retrain workaround). No matching report found as of
2026-09-22.
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