Public bug reported:
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.
** Affects: linux-hwe-6.14 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble
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https://bugs.launchpad.net/bugs/2133463
Title:
Touchpad and HDMI regression on Dell Precision 7780 after kernel
6.14.0-27 → 6.14.0-33+ update
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