Public bug reported:
**Problem description**
The touchpad on my Lenovo ThinkPad T14 Gen 4 AMD stopped working after a
reboot. It had previously worked normally, including on Ubuntu 26.04.
The TrackPoint (red pointing stick) and physical touchpad buttons still
work, but the touch-sensitive surface does not respond to finger
movement or gestures.
**Hardware:**
- Laptop: Lenovo ThinkPad T14 Gen 4 AMD
- Machine model: 21K4S02000
- Touchpad ACPI ID: ELAN0677:00
- I2C controller: AMDI0010:01
- System firmware: 1.51
**Operating system:**
- Ubuntu 26.04.1 LTS (Resolute Raccoon)
- Current kernel: 7.0.0-38-generic
- Also tested with kernel 6.8.0-146-generic
**Kernel errors previously observed:**
```
i2c_designware AMDI0010:01: i2c_dw_handle_tx_abort: lost arbitration
i2c_designware AMDI0010:01: i2c_dw_handle_tx_abort: lost arbitration
i2c_designware AMDI0010:01: i2c_dw_handle_tx_abort: lost arbitration
i2c_designware AMDI0010:01: i2c_dw_handle_tx_abort: lost arbitration
```
**Diagnostic findings:**
- The touchpad appears as `ELAN0677:00` on the I2C bus.
- ACPI reports device status 15 (present and enabled).
- The `i2c_hid_acpi` module is loaded but is not bound to the touchpad.
- The I2C controller `AMDI0010:01` is bound to the `i2c_designware` driver.
- `/sys/bus/i2c/devices/i2c-ELAN0677:00/waiting_for_supplier` returns 0.
- `/sys/kernel/debug/devices_deferred` is empty.
- Attempting to reprobe the device using `/sys/bus/i2c/drivers_probe` returns
`No such device (ENODEV)`.
**Troubleshooting already performed:**
1. Tested kernels 6.8.0-146 and 7.0.0-38. The touchpad does not work reliably
with either.
2. Reloaded `i2c_hid_acpi` and `i2c_hid` modules without success.
3. Tested `i8042.nopnp`, which appeared to help intermittently in the past, but
no longer resolves the problem.
4. Tested Zorin OS from a live USB. The touchpad surface did not work there
either.
5. Confirmed that the system firmware is up to date according to fwupd.
6. Tested a full power shutdown without success.
**Expected result:**
The touchpad surface should work normally, including pointer movement,
tapping, scrolling and gestures.
**Actual result:**
The touchpad surface does not respond. The TrackPoint and physical
buttons continue to work.
**Additional information:**
The problem is intermittent historically: the touchpad worked normally
until recently and occasionally resumed working after changes to boot
parameters or subsequent reboots.
The error messages suggest a possible issue with AMD I2C DesignWare
arbitration or HID-over-I2C initialization.
Please investigate whether this is related to an existing AMD I2C
controller regression and whether a kernel fix is available for the
ThinkPad T14 Gen 4 AMD.
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: pass
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 13 16:21:27 2026
InstallationDate: Installed on 2023-10-09 (1100 days ago)
InstallationMedia: Ubuntu 22.04.1 LTS "Jammy Jellyfish" - Release amd64
(20220809.1)
MachineType: LENOVO 21K4S02000
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-38-generic
root=UUID=5325f9a7-ce17-48ef-a143-e1ad43b9b699 ro quiet splash i8042.nopnp
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-10-12 (1 days ago)
dmi.bios.date: 08/13/2026
dmi.bios.release: 1.51
dmi.bios.vendor: LENOVO
dmi.bios.version: R2FET71W (1.51 )
dmi.board.asset.tag: Not Available
dmi.board.name: 21K4S02000
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.ec.firmware.release: 1.35
dmi.modalias:
dmi:bvnLENOVO:bvrR2FET71W(1.51):bd08/13/2026:br1.51:efr1.35:svnLENOVO:pn21K4S02000:pvrThinkPadT14Gen4:rvnLENOVO:rn21K4S02000:rvrNotDefined:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21K4_BU_Think_FM_ThinkPadT14Gen4:pfaThinkPadT14Gen4:
dmi.product.family: ThinkPad T14 Gen 4
dmi.product.name: 21K4S02000
dmi.product.sku: LENOVO_MT_21K4_BU_Think_FM_ThinkPad T14 Gen 4
dmi.product.version: ThinkPad T14 Gen 4
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2170713
Title:
Lenovo ThinkPad T14 Gen 4 AMD: ELAN0677 touchpad not working, I2C lost
arbitration errors
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2170713/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
