Re: Regression: Backlight control broken on HP Omen 1 5‑ax246nf with kernel 7.0.0‑28‑generic

On 7/18/26 11:05, harryblanc wrote:
> 
> I would like to report a regression affecting backlight control on my HP
> Omen laptop when using kernel 7.0.0‑28‑generic (Ubuntu 24.04 base, Linux
> Mint 22.3 XFCE).

Hi! Thx for your report. But this is a heavily patched vendor kernel and
also a series that is EOL. Please test latest vanilla 7.2-rc or and
report back. Ciao, Thorsten
> Summary of the issue:
> With kernel 7.0, the screen backlight is stuck at maximum brightness.
> Brightness keys show the OSD and the slider moves, but the actual
> backlight does not change.
> With kernel 6.17, brightness works normally.
> 
> Hardware:
> - HP Omen 15‑ax246nf
> - Intel i5‑7300HQ
> - Intel HD Graphics 630 (i915)
> - Nvidia GTX 1050 Mobile (disabled via Optimus)
> - Linux Mint 22.3 XFCE (Ubuntu 24.04 base)
> 
> Backlight controller:
> /sys/class/backlight/ → intel_backlight
> acpi_video0 is no longer present under kernel 7.0.
> 
> ACPI errors visible only with kernel 7.0:
> ACPI BIOS Error (bug): Attempt to CreateField of length zero
> ACPI Error: Aborting method \_SB.WMID.WQBK
> ACPI BIOS Error (bug): AE_AML_BUFFER_LIMIT
> ACPI Error: Aborting method \_SB.WMID.HWMC
> ACPI: video: [Firmware Bug]: ACPI(PEGP) defines _DOD but not _DOS
> 
> Kernel version:
> Linux 7.0.0-28-generic #28~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Jul 1
> 15:50:57 UTC 2024 x86_64 GNU/Linux
> 
> GPU information (inxi -Gxxx):
> Device-1: Intel HD Graphics 630 driver: i915
> Device-2: NVIDIA GTX 1050 Mobile driver: N/A (Optimus disabled)
> Display: X11 driver: modesetting, iris
> Monitor: eDP-1 1920x1080 LG Display
> 
> Hardware summary (lshw -short):
> Intel(R) Core(TM) i5-7300HQ
> HD Graphics 630
> GeForce GTX 1050 Mobile (disabled)
> 16 GiB DDR4
> Samsung NVMe SSD + 1TB HDD
> 
> Expected behavior:
> Backlight should be adjustable via intel_backlight or acpi_video0, as in
> kernel 6.17.
> 
> Observed behavior:
> Backlight remains at maximum brightness regardless of ACPI events or
> brightness keys.
> 
> Steps to reproduce:
> 1. Boot kernel 7.0.0‑28‑generic
> 2. Attempt to change brightness
> 3. Backlight does not change
> 
> This appears to be an ACPI/i915 regression introduced in kernel 7.0.
> 
> Thank you for your work.
>