Public bug reported:
## Summary
On Ubuntu 24.04 LTS, my Lenovo ThinkPad L14 Gen 1 AMD intermittently
experiences USB enumeration failures during boot.
The internal MediaTek Bluetooth device repeatedly produces USB
descriptor timeouts, followed by xHCI setup command timeouts and USB
enumeration failures.
On some affected boots, amdgpu initialization is delayed until
approximately 71–73 seconds after startup. GNOME Shell crashes and
graphical login failures have also been observed.
However, USB timeouts can also occur without delayed GPU initialization
or visible graphical problems.
## System Information
- Ubuntu 24.04 LTS
- Lenovo ThinkPad L14 Gen 1 AMD (20U6S4FT00)
- AMD Radeon Graphics (Renoir, 1002:1636)
- GNOME on Wayland
- System Firmware: 0.1.37
- Current kernel: 6.8.0-149-generic
- Earlier affected kernels: 6.8.0-147-generic and 6.8.0-138-generic
- Kernel parameter: amdgpu.dcdebugmask=0x10
Relevant devices:
- Internal MediaTek Bluetooth (0489:e0cd): usb 3-4
- External Lenovo ThinkPad Compact USB Keyboard with TrackPoint (17ef:6047):
usb 3-2
- xHCI controller: 0000:06:00.4
- AMD GPU: 0000:06:00.0
## Steps to Reproduce
1. Boot Ubuntu normally.
2. Restart the computer.
3. Observe USB initialization and the graphical login screen.
The problem is intermittent and cannot be reproduced reliably on every
restart.
## Actual Results
### November 6, 2026 — 08:55 JST, kernel 6.8.0-147
The following sequence was recorded:
- 7.01 seconds: USB descriptor timeout (-110).
- 49.91 seconds: xHCI setup command timeout.
- 67.01 seconds: USB enumeration failure (-62).
- 72.89 seconds: amdgpu initialization completed.
A GNOME Shell SIGSEGV was recorded at 08:57:06 JST in the GNOME greeter
environment.
The login screen appeared normal during this particular boot.
### November 6, 2026 — 13:49 JST, kernel 6.8.0-147
A very similar sequence occurred:
- 7.01 seconds: USB descriptor timeout (-110).
- 49.93 seconds: xHCI setup command timeout.
- 67.04 seconds: USB enumeration failure (-62).
- 71.21 seconds: amdgpu initialization completed.
The external USB keyboard's TrackPoint stopped responding, while the
laptop's built-in TrackPoint remained usable.
Two mouse pointers appeared. After the active pointer was moved over the
stationary pointer, the screen went black.
The display did not recover after approximately three minutes, and a
forced shutdown was required.
A subsequent journal search did not find a GNOME Shell crash entry for
this boot.
### November 6 — External keyboard disconnected
After disconnecting the external USB keyboard, kernel 6.8.0-147 booted
and the graphical login completed normally.
No USB enumeration or xHCI setup timeouts were found in the examined
logs. The AMD GPU framebuffer was available at approximately 7.53
seconds.
However, USB suspend errors (-110) were still recorded for the internal
Bluetooth device.
This was a single observation and does not establish that the external
keyboard caused the problem.
### November 7, 2026 — Kernel 6.8.0-149
With the external USB keyboard disconnected, Ubuntu booted and logged in
normally.
Nevertheless, USB enumeration failures and xHCI timeouts continued:
```text
[ 7.008383] usb 3-4: device descriptor read/64, error -110
[ 49.975394] xhci_hcd 0000:06:00.4: Timeout while waiting for setup device
command
[ 67.094613] usb 3-4: device not accepting address 6, error -62
```
In this boot, amdgpu initialization completed much earlier:
```text
[ 7.124881] [drm] Initialized amdgpu 3.57.0 20150101 for 0000:06:00.0 on
minor 1
```
No duplicate pointers or black screen occurred.
Therefore, USB enumeration failures do not always coincide with delayed
amdgpu initialization or visible graphical failures.
## Additional Information
Similar graphical login issues and external TrackPoint failures occurred
on October 29–30, including after switching from kernel 6.8.0-147 to
6.8.0-138.
The problem also recurred after updating Mesa to 25.2.8 and GNOME Shell
to 46.0-0ubuntu6~24.04.17.
The relationship between the USB failures, GPU initialization delays,
graphical login problems, and the external keyboard remains unknown.
No hardware failure has been confirmed.
## Expected Results
USB devices should initialize reliably after boot and restart.
The graphical login should work normally without duplicate pointers,
black screens, or forced shutdowns.
## Diagnostic Information
Selected kernel logs from affected and unaffected boots, GNOME Shell
crash metadata, and system information are available as attachments.
The original Apport report is retained locally but has not been uploaded
because it has not been fully cleared for public disclosure.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2173610
Title:
Intermittent USB enumeration timeouts on ThinkPad L14 Gen 1 AMD,
sometimes accompanied by delayed amdgpu initialization and graphical
login failure
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2173610/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
