I can confirm the same issue on a Dell Alienware Aurora 16X. System: - Hybrid graphics (Intel iGPU + NVIDIA RTX 5070) - NVIDIA driver 595.58.03 (also tested with nouveau) - Desktop: Cinnamon (Xorg)
Behavior: - Brightness keys work (KEY_BRIGHTNESSUP/DOWN events are generated) - Desktop slider appears and changes - Values in /sys/class/backlight/*/brightness change correctly - However, the screen brightness does not change at all Tested configurations: - Kernel 6.14 → issue present - Kernel 6.8 → issue present - acpi_backlight=video → acpi_video0 appears but no effect - acpi_backlight=vendor → no effect - video.use_native_backlight=1 → no effect - intel_backlight and acpi_video0 both ineffective Additional observation: - Forcing Intel-only mode in BIOS results in black screen (except safe mode), suggesting the panel is not directly controlled by Intel backlight This appears to be related to backlight routing / EC / GPU path on modern hybrid laptops. Additional information: 00:00.0 Host bridge [0600]: Intel Corporation Device [8086:7d1c] (rev 01) 00:01.0 PCI bridge [0604]: Intel Corporation Device [8086:7ecc] (rev 10) 00:02.0 VGA compatible controller [0300]: Intel Corporation Arrow Lake-U [Intel Graphics] [8086:7d67] (rev 06) 00:04.0 Signal processing controller [1180]: Intel Corporation Device [8086:ad03] (rev 01) 00:06.0 PCI bridge [0604]: Intel Corporation Device [8086:ae4d] (rev 10) 00:06.4 PCI bridge [0604]: Intel Corporation Device [8086:ae4f] (rev 10) 00:07.0 PCI bridge [0604]: Intel Corporation Meteor Lake-P Thunderbolt 4 PCI Express Root Port #0 [8086:7ec4] (rev 10) 00:08.0 System peripheral [0880]: Intel Corporation Device [8086:ae4c] (rev 10) 00:0a.0 Signal processing controller [1180]: Intel Corporation Device [8086:ad0d] (rev 01) 00:0b.0 Processing accelerators [1200]: Intel Corporation Arrow Lake NPU [8086:ad1d] (rev 01) 00:0d.0 USB controller [0c03]: Intel Corporation Meteor Lake-P Thunderbolt 4 USB Controller [8086:7ec0] (rev 10) 00:0d.2 USB controller [0c03]: Intel Corporation Meteor Lake-P Thunderbolt 4 NHI #0 [8086:7ec2] (rev 10) 00:14.0 RAM memory [0500]: Intel Corporation Device [8086:ae7f] (rev 10) 00:1f.0 ISA bridge [0601]: Intel Corporation Device [8086:ae10] (rev 10) 00:1f.5 Serial bus controller [0c80]: Intel Corporation Device [8086:ae23] (rev 10) 01:00.0 Non-Volatile memory controller [0108]: SK hynix Device [1c5c:1069] 02:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:2f58] (rev a1) 02:00.1 Audio device [0403]: NVIDIA Corporation Device [10de:2f80] (rev a1) 03:00.0 Non-Volatile memory controller [0108]: Samsung Electronics Co Ltd NVMe SSD Controller PM9A1/PM9A3/980PRO [144d:a80a] 80:12.0 Serial controller [0700]: Intel Corporation Device [8086:7f78] (rev 10) 80:14.0 USB controller [0c03]: Intel Corporation Device [8086:7f6e] (rev 10) 80:14.5 Non-VGA unclassified device [0000]: Intel Corporation Device [8086:7f2f] (rev 10) 80:16.0 Communication controller [0780]: Intel Corporation Device [8086:7f68] (rev 10) 80:19.0 Serial bus controller [0c80]: Intel Corporation Device [8086:7f7a] (rev 10) 80:1c.0 PCI bridge [0604]: Intel Corporation Device [8086:7f3d] (rev 10) 80:1c.6 PCI bridge [0604]: Intel Corporation Device [8086:7f3e] (rev 10) 80:1f.0 ISA bridge [0601]: Intel Corporation Device [8086:7f0c] (rev 10) 80:1f.3 Audio device [0403]: Intel Corporation Device [8086:7f50] (rev 10) 80:1f.4 SMBus [0c05]: Intel Corporation Device [8086:7f23] (rev 10) 80:1f.5 Serial bus controller [0c80]: Intel Corporation Device [8086:7f24] (rev 10) 81:00.0 Network controller [0280]: MEDIATEK Corp. Device [14c3:7925] 82:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 15) Providers: number : 2 Provider 0: id: 0x45 cap: 0x9, Source Output, Sink Offload crtcs: 4 outputs: 3 associated providers: 1 name:modesetting Provider 1: id: 0x209 cap: 0x2, Sink Output crtcs: 4 outputs: 4 associated providers: 1 name:NVIDIA-G0 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2134615 Title: ASUS TUF A16 (FA608WI): backlight interfaces present but do not change panel brightness (AMD iGPU + NVIDIA dGPU) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-hwe-6.14/+bug/2134615/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
