Touchpad and HDMI regression on Dell Precision 7780 after kernel 6.14.0-27 → 6.14.0-33+ update

[Mohamed Safouane BOUABID]

Description:
This is a regression affecting both the touchpad and HDMI output on my Dell Precision 7780 when upgrading from kernel 6.14.0-27 to 6.14.0-33, 6.14.0-35, and 6.14.0-36.

Hardware

Model: Dell Precision 7780

Touchpad: VEN_0488:00 0488:1064 (ELAN HID over I²C device)

GPU: Intel integrated graphics (i915)

GOOD Kernel

6.14.0-27-generic
Touchpad works perfectly:

Full smooth cursor movement

Two-finger scrolling

Tap-to-click

Gestures

No freezing or missing events
HDMI output also works normally (TV detected immediately).

BAD Kernels

6.14.0-33-generic

6.14.0-35-generic

6.14.0-36-generic

linux-oem-24.04 (current OEM kernel)

All exhibit identical failures.

Touchpad Regression Symptoms

On the affected kernels:

Cursor moves only 1–2 cm and then stops

Often no cursor movement at all

No two-finger scrolling

No tap-to-click

Physical click works

Touchpad shows up in libinput but motion events suddenly stop

libinput debug-events shows a burst of POINTER_MOTION events followed by complete silence

Sometimes only a fallback “Mouse” interface from the same device works partially

Pointer intermittently enters a “partial working” state; then driver stops reporting motion entirely

This indicates a regression in HID over I²C (likely in i2c_hid_acpi, i2c_designware, or ACPI HID parsing).

The touchpad works perfectly in BIOS, which uses PS/2 mode, so this is not a hardware fault.

HDMI Regression Symptoms

On kernels > 6.14.0-27:

External TV/monitor not detected at all

No HDMI hotplug events

Display Settings shows only internal panel

xrandr does not list the HDMI connector

Switching back to 6.14.0-27 makes HDMI work immediately again

This suggests a broader regression in either:

The i915 graphics driver, or

ACPI/firmware interactions affecting both display and I²C buses

Both regressions appeared together after upgrading past 6.14.0-27.

Summary

Works: kernel 6.14.0-27

Broken: kernels 6.14.0-33 / 35 / 36 + OEM

Symptoms indicate a regression in the I²C HID stack and possibly Intel HDMI handling.

This is fully reproducible and goes away by selecting kernel 6.14.0-27 in GRUB.

Please let me know if more logs or journalctl -k excerpts are needed.

ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-6.14.0-27-generic 6.14.0-27.27~24.04.1
ProcVersionSignature: Ubuntu 6.14.0-27.27~24.04.1-generic 6.14.6
Uname: Linux 6.14.0-27-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.28.1-0ubuntu3.8
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: safwen 7319 F.... wireplumber
 /dev/snd/controlC0: safwen 7319 F.... wireplumber
 /dev/snd/seq: safwen 7312 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun Nov 30 18:15:43 2025
InstallationDate: Installed on 2024-10-25 (401 days ago)
InstallationMedia: Ubuntu 24.04.1 LTS "Noble Numbat" - Release amd64 (20240827.1)
MachineType: Dell Inc. Precision 7780
ProcEnviron:
 LANG=en_US.UTF-8
 PATH=(custom, no user)
 SHELL=/bin/bash
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.14.0-27-generic root=UUID=a87cbeba-2566-40df-a6bf-7d2cac7268aa ro quiet splash resume=UUID=a87cbeba-2566-40df-a6bf-7d2cac7268aa resume_offset=164059136 vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-6.14.0-27-generic N/A
 linux-backports-modules-6.14.0-27-generic N/A
 linux-firmware 20240318.git3b128b60-0ubuntu2.21
SourcePackage: linux-hwe-6.14
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/05/2025
dmi.bios.release: 1.25
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.25.0
dmi.board.name: 0R1G0M
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.ec.firmware.release: 1.20
dmi.modalias: dmi:bvnDellInc.:bvr1.25.0:bd09/05/2025:br1.25:efr1.20:svnDellInc.:pnPrecision7780:pvr:rvnDellInc.:rn0R1G0M:rvrA00:cvnDellInc.:ct10:cvr:sku0C42:
dmi.product.family: Precision
dmi.product.name: Precision 7780
dmi.product.sku: 0C42
dmi.sys.vendor: Dell Inc.

[Daniel Letzeisen (dtl131)]

Probably a duplicate of bug 2115148
A number of people report problems with keyboard/mouse/wifi/touchpad/video after experiencing that bug because the kernel does not install/configure correctly.

I'm guessing HDMI is wired to the Nvidia GPU and Nvidia driver is not loading.