Public bug reported:
Hardware: ASRock B850I Lightning WiFi, Radeon RX 7900 XTX (Navi 31), Raphael
iGPU unused for display.
Monitors: Samsung LS24AG32x at 165 Hz on DP-1 and LG ULTRAWIDE at 75 Hz on
DP-2, both on the RX 7900 XTX.
With the two monitors at different refresh rates, the display shows artifacting:
[what it looks like, e.g. flickering lines or blocks, which monitor, and when:
idle, moving windows, video].
Good: 7.0.0-34-generic, no artifacting in normal use.
Bad: 7.0.0-38-generic (the build released to resolute-updates). Also seen on
7.0.0-28.
Possibly related changes in 7.0.0-38 that are not in 7.0.0-34:
- drm/amd/display: consolidate DCN vblank/flip handling
- drm/amd/display: Fix DTB DTO updates breaking live pixel rate sources
- drm/amd/display: Fix mem_type change detection for async flips
- the ISM fixes for LP: #2163121
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-38-generic 7.0.0-38.38
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Fri Oct 2 14:17:29 2026
InstallationDate: Installed on 2025-11-07 (329 days ago)
InstallationMedia: Kubuntu 25.10 "Questing Quokka" - Release amd64 (20251007)
IwDevWlp10s0Link: Not connected.
MachineType: ASRock B850I Lightning WiFi
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-38-generic
root=UUID=b80b57ad-ad0b-4866-844f-72c840a6557d ro maxcpus=12 smt=on
nvme_core.io_timeout=4
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-02-15 (229 days ago)
dmi.bios.date: 06/24/2026
dmi.bios.release: 5.41
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: 4.43
dmi.board.asset.tag: Default string
dmi.board.name: B850I Lightning WiFi
dmi.board.vendor: ASRock
dmi.board.version: Default string
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias:
dmi:bvnAmericanMegatrendsInternational,LLC.:bvr4.43:bd06/24/2026:br5.41:svnASRock:pnB850ILightningWiFi:pvrDefaultstring:rvnASRock:rnB850ILightningWiFi:rvrDefaultstring:cvnDefaultstring:ct3:cvrDefaultstring:skuDefaultstring:pfaDefaultstring:
dmi.product.family: Default string
dmi.product.name: B850I Lightning WiFi
dmi.product.sku: Default string
dmi.product.version: Default string
dmi.sys.vendor: ASRock
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug regression-update resolute wayland-session
** Tags added: regression-update
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https://bugs.launchpad.net/bugs/2169237
Title:
amdgpu: display artifacting with mixed refresh rate DP monitors on
7.0.0-38, not on 7.0.0-34
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