Public bug reported:
Dock: Dell WD19TB, external monitor connected to it does not show up in
kubuntu 26.04 after "reboot" command. Rest of devices on the dock work
fine (usb keyboards etc).
It works from cold start.
What helps if this happens is either unplug the dock from both tb and power,
and reconnect, or do the following:
echo 0000:00:0d.2 | sudo tee /sys/bus/pci/drivers/thunderbolt/unbind
sleep 2
echo 0000:00:0d.2 | sudo tee /sys/bus/pci/drivers/thunderbolt/bind
Summary: DisplayPort-over-Thunderbolt external monitor not restored after warm
reboot on Meteor Lake — TB connection manager tears down the DP tunnel before
the GPU driver is ready, tunnel never recreated.
Hardware:
MSI Prestige 13 AI Evo A1MG (Meteor Lake-P)
Host TB: Intel Meteor Lake-P Thunderbolt 4 NHI #0 [8086:7ec2], driver
thunderbolt
Dock: Dell WD19TB (Intel JHL7440 Titan Ridge, Thunderbolt 3), single external
monitor via DP-over-TB
Session: Wayland (KDE Plasma), Kubuntu 26.04
Kernel: 7.0.0-27-generic #27-Ubuntu SMP PREEMPT_DYNAMIC Thu Jun 18 2026
What happens: After a warm reboot (reboot, not cold power-off), the external
monitor connected via DisplayPort-over-Thunderbolt stays dark. Cold boot works;
warm reboot does not. dmesg shows the DP tunnel being torn down among the
earliest kernel messages, i.e. before the i915/xe display driver is up:
thunderbolt 0-3: Dell WD19TB Thunderbolt Dock
thunderbolt 0-0:3.1: new retimer found, vendor=0x8087 device=0xd9c
thunderbolt 0000:00:0d.2: 0:5 <-> 3:11 (DP): not active, tearing down
The tunnel is destroyed and never recreated, because at teardown time the DP
source (iGPU) is not yet driving it, and no later hotplug event triggers
re-tunneling.
Recovery (confirms HW is fine, this is a boot-ordering race):
Physically unplugging/replugging the TB cable after boot → monitor comes up
immediately, or
Rebinding the NHI after the GPU driver is loaded works too:
echo 0000:00:0d.2 > /sys/bus/pci/drivers/thunderbolt/unbind
echo 0000:00:0d.2 > /sys/bus/pci/drivers/thunderbolt/bind
Regression note: Probably similar teardown signature as reported on Ubuntu
26.04 for Panther Lake/xe, where 7.0.0-22 regressed and 7.0.0-15 worked. I'm on
7.0.0-27 on Meteor Lake and it still occurs — so the fix has not landed for
this platform.
Workaround in use: systemd oneshot unit that rebinds the NHI after
graphical.target.
boltctl shows the dock authorizes cleanly (iommu+user, auto-auth OK), so this
is not an authorization issue.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-27-generic 7.0.0-27.27
ProcVersionSignature: Ubuntu 7.0.0-27.27-generic 7.0.6
Uname: Linux 7.0.0-27-generic x86_64
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Tue Jul 14 12:38:15 2026
InstallationDate: Installed on 2026-07-13 (1 days ago)
InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423)
MachineType: Micro-Star International Co., Ltd. Prestige 13 AI Evo A1MG
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-27-generic
root=UUID=523ca483-c48f-4f58-bf0b-74682d2d8535 ro quiet
cryptdevice=UUID=77a13756-e087-418d-857e-9bd8d72aa6d5:luks-77a13756-e087-418d-857e-9bd8d72aa6d5
root=/dev/mapper/luks-77a13756-e087-418d-857e-9bd8d72aa6d5 splash
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/04/2025
dmi.bios.release: 1.13
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: E13Q2IMS.10D
dmi.board.asset.tag: Default string
dmi.board.name: MS-13Q2
dmi.board.vendor: Micro-Star International Co., Ltd.
dmi.board.version: REV:1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: Micro-Star International Co., Ltd.
dmi.chassis.version: N/A
dmi.modalias:
dmi:bvnAmericanMegatrendsInternational,LLC.:bvrE13Q2IMS.10D:bd11/04/2025:br1.13:svnMicro-StarInternationalCo.,Ltd.:pnPrestige13AIEvoA1MG:pvrREV1.0:rvnMicro-StarInternationalCo.,Ltd.:rnMS-13Q2:rvrREV1.0:cvnMicro-StarInternationalCo.,Ltd.:ct10:cvrN/A:sku13Q2.1:pfaPrestige:
dmi.product.family: Prestige
dmi.product.name: Prestige 13 AI Evo A1MG
dmi.product.sku: 13Q2.1
dmi.product.version: REV:1.0
dmi.sys.vendor: Micro-Star International Co., Ltd.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2160608
Title:
DisplayPort-over-Thunderbolt external monitor not detected at warm-
boot
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