Public bug reported:
My system is experiencing intermittent hard freezes requiring a forced
reboot. The issue appears to be related to the graphics driver
negotiation with the external display/dock.
Immediately around the time of the freeze, the system logs the following
kernel error regarding DisplayPort Link Training (LTTPR):
"[drm] *ERROR* LTTPR count is nonzero but invalid lane count reported.
Assuming no LTTPR present."
OS: Ubuntu 25.10
Kernel: 6.17.0-8-generic
Hardware: RTX 3090, AMD 7800 CPU
Symptoms:
The screen freezes or goes black unexpectedly.
The system becomes unresponsive to keyboard/mouse input.
The error log suggests the GPU driver (likely amdgpu or i915) is failing
to negotiate the lane count with the display repeater/dock.
Please advise how to address this issue.
ProblemType: Bug
DistroRelease: Ubuntu 25.10
Package: linux-image-generic 6.17.0-8.8
ProcVersionSignature: Ubuntu 6.17.0-8.8-generic 6.17.2
Uname: Linux 6.17.0-8-generic x86_64
ApportVersion: 2.33.1-0ubuntu3
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun Jan 18 11:56:44 2026
InstallationDate: Installed on 2025-03-24 (300 days ago)
InstallationMedia: Ubuntu 24.10 "Oracular Oriole" - Release amd64 (20241009.4)
MachineType: ASRock B650 Steel Legend WiFi
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.17.0-8-generic
root=UUID=0bb38b9b-1bd8-4731-8b42-5725fdc2c57c ro quiet splash
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
vt.handoff=7
RelatedPackageVersions:
firmware-sof N/A
linux-firmware 20250901.git993ff19b-0ubuntu1.5
SourcePackage: linux
UpgradeStatus: Upgraded to questing on 2025-11-01 (78 days ago)
dmi.bios.date: 02/21/2025
dmi.bios.release: 5.35
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: 3.20
dmi.board.asset.tag: Default string
dmi.board.name: B650 Steel Legend 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.:bvr3.20:bd02/21/2025:br5.35:svnASRock:pnB650SteelLegendWiFi:pvrDefaultstring:rvnASRock:rnB650SteelLegendWiFi:rvrDefaultstring:cvnDefaultstring:ct3:cvrDefaultstring:skuDefaultstring:
dmi.product.family: Default string
dmi.product.name: B650 Steel Legend 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 questing wayland-session
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https://bugs.launchpad.net/bugs/2138570
Title:
amdgpu 0000:0d:00.0: [drm] *ERROR* LTTPR count is nonzero but invalid
lane count reported. Assuming no LTTPR present.
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