https://bugzilla.kernel.org/show_bug.cgi?id=221648
Bug ID: 221648
Summary: HP OMEN 16-am0015ns: brightness control non-functional
- ACPI _BCM/_BCL/_BQC misplaced under NVIDIA subtree
instead of GFX0 (Intel Arrow Lake-P / Meteorlake)
Product: ACPI
Version: 2.5
Hardware: All
OS: Linux
Status: NEW
Severity: normal
Priority: P3
Component: ACPICA-Core
Assignee: [email protected]
Reporter: [email protected]
Regression: No
Created attachment 310317
--> https://bugzilla.kernel.org/attachment.cgi?id=310317&action=edit
Disassembled ACPI DSDT (HPQOEM 8D2F, OEM revision 01072009) - brightness
methods _BCM/_BCL/_BQC misplaced under NVIDIA subtree PEGB/PEGE/DEDP instead of
GFX0
Summary
On an HP OMEN Gaming Laptop 16-am0015ns with Intel Arrow Lake-P iGPU and NVIDIA
RTX 5060 Max-Q dGPU, panel backlight cannot be adjusted from Linux. Brightness
keys, GUI sliders, and direct sysfs writes all have no visible effect on the
panel.
Related to kernel bugzilla #221530 (HP OMEN MAX 16-ah0xxx, same symptom, Arrow
Lake + RTX 5080).
System Information
Model: HP OMEN Gaming Laptop 16-am0015ns (SKU BP4Q7EA#ABE, Serial 5CD5254G4V)
Board: HP 8D2F, version 75.54
BIOS: AMI F.14, released 04/14/2026 — latest available
iGPU: Intel Arrow Lake-P [Arc Pro 130T/140T] 8086:7d51 rev 03 — 0000:00:02.0,
driver i915
dGPU: NVIDIA GeForce RTX 5060 Max-Q / Mobile (GB206M) 10de:2d19 rev a1 —
0000:01:00.0, driver nvidia 595.80
Kernel: 7.0.12-201.fc44.x86_64
Distribution: Fedora 44 KDE Plasma
Session type: Wayland
Display panel: BOE, Product code 0x0CF1, manufactured 2024 week 13
Kernel Command Line
rd.driver.blacklist=nouveau,nova_core modprobe.blacklist=nouveau,nova_core
nvidia_drm.modeset=1 acpi_backlight=native i915.enable_dpcd_backlight=1
Root Cause: ACPI DSDT Analysis
The DSDT (HPQOEM 8D2F, OEM revision 01072009) contains brightness control
methods _BCM, _BCL, _BQC, but they are placed under the NVIDIA PCIe device
subtree, not under the Intel IGD device (GFX0):
\_SB.PCI0
├── GFX0 (_ADR 0x00020000 → Intel Arc, 0000:00:02.0)
│ └── [NO _BCL / _BCM / _BQC defined here]
│
└── PEGB (_ADR 0x00010000 → PCIe slot, leads to NVIDIA 0000:01:00.0)
└── PEGE (_ADR 0x0000)
└── DEDP (eDP display device)
├── _BCL → brightness levels 0x00..0x64
├── _BCM → brightness set method
└── _BQC → brightness query
The _BCM method writes to Intel IGD OpRegion fields (BCLP, ASLC), which is
correct — but the i915 driver never calls it because it only searches for these
methods under its own ACPI device node (GFX0), not under the NVIDIA subtree:
Method (_BCM, 1, NotSerialized)
{
If (((Arg0 >= Zero) && (Arg0 <= 0x64)))
{
BCLP = ((Arg0 * 0xFF) / 0x64)
BCLP |= 0x80000000
ASLC = 0x02
DBRL = Arg0
}
}
Additional ACPI Errors at Boot
[6.782295] ACPI BIOS Error: AE_AML_BUFFER_LIMIT, Index (0x000000032) is beyond
end of object (length 0x32)
[6.782315] ACPI Error: Aborting method \_SB.WMID.WQBZ
[6.789875] hp_bioscfg: Returned error 0x3, "Invalid command value/Feature not
supported"
Repeated i915 Errors
[77.319796] i915 0000:00:02.0: [drm] *ERROR* Atomic update failure on pipe A
[170.426431] i915 0000:00:02.0: [drm] *ERROR* Atomic update failure on pipe A
[301.775833] i915 0000:00:02.0: [drm] *ERROR* Atomic update failure on pipe A
nvidia_wmi_ec_backlight
Module is present but WMI GUID 603E9613-EF25-4338-A3D0-C46177516DB7 is absent
from this firmware. Loading with force=1 creates no backlight interface.
Everything Already Tried (All Ineffective)
acpi_backlight=nvidia — no nvidia_backlight interface created
acpi_backlight=native — only intel_backlight, writes have no effect
i915.enable_dpcd_backlight=1 — parameter active, no DPCD negotiation in dmesg
echo N | sudo tee /sys/class/backlight/intel_backlight/brightness — accepted,
no visual change
sudo modprobe nvidia_wmi_ec_backlight force=1 — loads, no interface created,
WMI GUID absent
ddcutil / ddccontrol — panel does not support DDC/CI
kscreen-doctor output.eDP-1.brightness.N — no visual change
qdbus setBrightness — moves KDE slider, no visual change
Proposed Fix
The i915 driver should be extended, or a quirk added for device ID 8086:7d51 /
HP board 8D2F, to search for _BCM/_BCL/_BQC methods not only under the IGD ACPI
device (GFX0) but also under sibling display devices (such as DEDP under the
PCIe/NVIDIA subtree) when the panel is physically driven by the iGPU.
Alternatively, HP should move the _BCM/_BCL/_BQC methods to GFX0 in a future
BIOS update.
Related
Kernel bugzilla #221530: https://bugzilla.kernel.org/show_bug.cgi?id=221530
NVIDIA open-gpu-kernel-modules #1202:
https://github.com/NVIDIA/open-gpu-kernel-modules/issues/1202
NVIDIA open-gpu-kernel-modules #1087:
https://github.com/NVIDIA/open-gpu-kernel-modules/issues/1087
Disassembled DSDT available on request.
--
You may reply to this email to add a comment.
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
acpi-bugzilla mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla
