Re: [PATCH] ACPI: video: force native backlight on HP OMEN 16 (8A44)

[Shivam Kalra]

On 26/04/26 19:38, Shivam Kalra via B4 Relay wrote:
> From: Shivam Kalra <shivamkalra98@xxxxxxxxxxx>
>
> The HP OMEN 16 Gaming Laptop (board name 8A44) has a mux-less hybrid
> GPU configuration with AMD Rembrandt (Radeon 680M) and NVIDIA GA104
> (RTX 3070 Ti). The internal eDP panel is wired to the AMD iGPU.
>
> When Nouveau loads without GSP firmware, the ACPI video backlight
> device (acpi_video0) gets registered alongside the native AMD
> backlight (amdgpu_bl2). In this state, writes to amdgpu_bl2 update
> the software brightness value but fail to change the physical panel
> brightness.
>
> Force native backlight to prevent acpi_video0 from registering.
> Confirmed that booting with acpi_backlight=native resolves the issue.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Shivam Kalra <shivamkalra98@xxxxxxxxxxx>
> ---
> This patch adds a DMI quirk to force native backlight control on the
> HP OMEN 16 Gaming Laptop (board name 8A44), which has a mux-less
> hybrid GPU configuration with AMD Rembrandt (680M iGPU) and NVIDIA
> GA104 (RTX 3070 Ti).
> On this laptop the internal eDP panel is wired to the AMD iGPU. The
> amdgpu driver registers amdgpu_bl2 as the native backlight device.
> When the Nouveau driver is loaded without GSP firmware (as is the
> case on v6.17 where GSP is not the default for Ampere GPUs), writes
> to amdgpu_bl2 fail silently — the brightness sysfs value updates
> but the physical panel brightness does not change.
> Testing:
> - Tested on HP OMEN 16 with AMD Ryzen 9 6900HX + NVIDIA RTX 3070 Ti.
> - On v6.17, without this quirk, brightness control is broken.
> - On v6.17, booting with acpi_backlight=native restores correct
>    brightness control. This patch applies that workaround
>    automatically via DMI match.
> - On v6.18+, the issue does not reproduce because commit
>    e0ed674acbac ("drm/nouveau: Remove DRM_NOUVEAU_GSP_DEFAULT
>    config") made GSP firmware the default for Ampere, which avoids
>    the ACPI conflict entirely.
> I have only tested this on v6.17 and v7.0. I am leaving it to the
> stable/LTS maintainers to determine whether this quirk should be
> backported, as I have not verified the stability of the GSP firmware
> path on intermediate releases.
>
> Thanks,
> Shivam Kalra
> ---
>   drivers/acpi/video_detect.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
> index 0a3c8232d15d..458efa4fe9d4 100644
> --- a/drivers/acpi/video_detect.c
> +++ b/drivers/acpi/video_detect.c
> @@ -916,6 +916,14 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
>   		DMI_MATCH(DMI_PRODUCT_NAME, "82K8"),
>   		},
>   	},
> +	{
> +	 .callback = video_detect_force_native,
> +	 /* HP OMEN Gaming Laptop 16-n0xxx */
> +	 .matches = {
> +		DMI_MATCH(DMI_SYS_VENDOR, "HP"),
> +		DMI_MATCH(DMI_PRODUCT_NAME, "OMEN by HP Gaming Laptop 16-n0xxx"),
> +		},
> +	},
>   
>   	/*
>   	 * x86 android tablets which directly control the backlight through
>
> ---
> base-commit: 27d128c1cff64c3b8012cc56dd5a1391bb4f1821
> change-id: 20260425-omen-16-backlight-fix-73fb8bc4a2b9
>
> Best regards,
> --
> Shivam Kalra <shivamkalra98@xxxxxxxxxxx>
Hey,

A gentle thread bump. If you have any suggestions let me know.

Shivam