Public bug reported:
## System information
- Laptop: HP ZBook Firefly 14 inch G11 A Mobile Workstation PC
- GPU: AMD HawkPoint1 (1002:1900), using `amdgpu`
- BIOS: W82 Ver. 01.09.02 (2026-08-21)
- OS: Ubuntu 26.04, upgraded from Ubuntu 24.04
- Kernels tested: 7.0.0-38-generic and 7.0.0-31-generic
- Session: GNOME Wayland
- External monitor: Ilyama monitor connected via USB-C, with integrated USB dock
## Problem
The external monitor was no longer detected via USB-C after upgrading
from Ubuntu 24.04 to Ubuntu 26.04. The same configuration had worked
before the upgrade.
USB keyboard and mouse connected to the monitor's integrated dock
continued to work.
Connecting the monitor directly via HDMI also worked.
## Diagnostics while the display was not working
All external DisplayPort connectors under `/sys/class/drm/` reported
`disconnected`. Only the internal display (`card1-eDP-1`) reported
`connected`.
Further Diagnostics:
- `/sys/class/typec/` was empty.
- The ACPI device `USBC000:00` existed with modalias `acpi:USBC000:PNP0CA0:`
and ACPI status `15`.
- The modules `ucsi_acpi`, `typec_ucsi`, `typec`, and `thunderbolt` were loaded.
- The `ucsi_acpi` driver was not bound to `USBC000:00`.
- Attempting to bind it manually returned `No such device (os error 19)`.
- Setting `driver_override` to `ucsi_acpi` and repeating the bind attempt
produced the same error.
- Reloading `ucsi_acpi` did not change the result.
- The kernel log contained entries for the HP UCSI ACPI tables but no further
UCSI-specific messages.
The kernel log also contained an `amdgpu` warning:
```
REG_WAIT timeout 1us * 100 tries -
dcn31_program_compbuf_size line:141
```
## Tests and recovery
Rebooting with the older Ubuntu kernel `7.0.0-31-generic` did not
restore the USB-C display. The problem was also present with
`7.0.0-38-generic`.
A full power reset of the laptop (disconnecting external power, pressing
power button for 15 seconds), restored the USB-C display.
## Diagnostics after recovery
With the external monitor working again:
```
/sys/class/drm/card1-DP-2/status: connected
/sys/class/drm/card1-eDP-1/status: connected
```
However:
- `/sys/class/typec/` remained empty.
- `USBC000:00` remained unbound to any driver.
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
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: josias 9084 F.... wireplumber
/dev/snd/controlC0: josias 9084 F.... wireplumber
/dev/snd/seq: josias 9064 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Oct 26 13:02:18 2026
InstallationDate: Installed on 2024-10-04 (752 days ago)
InstallationMedia: Ubuntu 24.04.1 LTS "Noble Numbat" - Release amd64
(20240827.1)
MachineType: HP HP ZBook Firefly 14 inch G11 A Mobile Workstation PC
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic
root=/dev/mapper/ubuntu--vg-ubuntu--lv ro amdgpu.dcdebugmask=0x10
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
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 2026-10-19 (7 days ago)
dmi.bios.date: 08/21/2026
dmi.bios.release: 9.2
dmi.bios.vendor: HP
dmi.bios.version: W82 Ver. 01.09.02
dmi.board.name: 8C6F
dmi.board.vendor: HP
dmi.board.version: KBC Version 04.55.00
dmi.chassis.type: 10
dmi.chassis.vendor: HP
dmi.ec.firmware.release: 4.85
dmi.modalias:
dmi:bvnHP:bvrW82Ver.01.09.02:bd08/21/2026:br9.2:efr4.85:svnHP:pnHPZBookFirefly14inchG11AMobileWorkstationPC:pvrSBKPFV3:rvnHP:rn8C6F:rvrKBCVersion04.55.00:cvnHP:ct10:cvr:skuA3YW4ET#ABH:pfa103C_5336ANHPZBook:
dmi.product.family: 103C_5336AN HP ZBook
dmi.product.name: HP ZBook Firefly 14 inch G11 A Mobile Workstation PC
dmi.product.sku: A3YW4ET#ABH
dmi.product.version: SBKPFV3
dmi.sys.vendor: HP
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute
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https://bugs.launchpad.net/bugs/2172227
Title:
USB-C external monitor not detected after upgrade to Ubuntu 26.04;
restored by full power reset
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