Public bug reported:
Similar to Bug #2161575 but I can reproduce this regression on different
hardware.
Hardware
--------
HP EliteBook x360 1030 G2
CPU
---
Intel Core i5-7300U
GPU
---
Intel HD Graphics 620 (PCI ID 8086:5916)
Ubuntu
------
Ubuntu 24.04 LTS
Kernel testing
--------------
PASS
- 6.8.0-136-generic
- brightness controls work
- suspend/resume works normally
PASS
- 6.17.0-40-generic
- brightness controls work
- suspend/resume works normally
FAIL
- 7.0.0-28-generic
Symptoms
--------
On 7.0.0-28, the internal display backlight is incorrect.
Brightness hotkeys no longer produce any visible change.
After suspend/resume, the internal display becomes almost completely
dark.
The system remains responsive.
The following values both report maximum brightness:
/sys/class/backlight/intel_backlight/brightness = 1023
/sys/class/backlight/intel_backlight/actual_brightness = 1023
Writing 0 and then 1023 to the intel_backlight sysfs interface does not
change the display brightness.
Reboot restores normal operation.
Additional testing
------------------
The kernel parameter:
i915.enable_dpcd_backlight=0
did not resolve the issue.
The only variable changed during testing was the kernel version.
This regression is reproducible on this HP EliteBook x360 1030 G2. Both
Linux 6.8.0-136 and 6.17.0-40 work correctly on the same hardware.
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-7.0.0-28-generic 7.0.0-28.28~24.04.1
ProcVersionSignature: Ubuntu 7.0.0-28.28~24.04.1-generic 7.0.12
Uname: Linux 7.0.0-28-generic x86_64
ApportVersion: 2.28.2-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: dnottage 2222 F.... wireplumber
/dev/snd/seq: dnottage 2217 F.... pipewire
CRDA: N/A
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Tue Jul 28 18:54:13 2026
InstallationDate: Installed on 2025-07-09 (385 days ago)
InstallationMedia: Ubuntu 24.04.2 LTS "Noble Numbat" - Release amd64 (20250215)
MachineType: HP HP EliteBook x360 1030 G2
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-7.0.0-28-generic
root=UUID=47e10415-1771-4cd9-839c-d04a36c1d6b7 ro quiet splash vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-7.0.0-28-generic N/A
linux-backports-modules-7.0.0-28-generic N/A
linux-firmware 20240318.git3b128b60-0ubuntu2.27
SourcePackage: linux-hwe-7.0
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/20/2021
dmi.bios.release: 1.39
dmi.bios.vendor: HP
dmi.bios.version: P80 Ver. 01.39
dmi.board.name: 827D
dmi.board.vendor: HP
dmi.board.version: KBC Version 44.79
dmi.chassis.type: 31
dmi.chassis.vendor: HP
dmi.ec.firmware.release: 68.121
dmi.modalias:
dmi:bvnHP:bvrP80Ver.01.39:bd04/20/2021:br1.39:efr68.121:svnHP:pnHPEliteBookx3601030G2:pvr:rvnHP:rn827D:rvrKBCVersion44.79:cvnHP:ct31:cvr:sku1BS97UT#ABA:pfa103C_5336ANHPEliteBookx360:
dmi.product.family: 103C_5336AN HP EliteBook x360
dmi.product.name: HP EliteBook x360 1030 G2
dmi.product.sku: 1BS97UT#ABA
dmi.sys.vendor: HP
** Affects: linux-hwe-7.0 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
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https://bugs.launchpad.net/bugs/2162026
Title:
Regression: Intel HD 620 backlight broken on HP EliteBook x360 1030 G2
with Linux 7.0.0-28 (works on 6.8 and 6.17)
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