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

[Rafael J. Wysocki]

On Tue, May 5, 2026 at 5:22 PM Shivam Kalra <shivamkalra98@xxxxxxxxxxx> wrote:
>
> 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.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4b506ea5351a1f5937ac632a4a5c35f6f796cc41

It looks like I have not responded to the patch, sorry about that.