ls /sys/class/backlight
nvidia_wmi_ec_backlight -> ../../devices/pci0000:00/PNP0C14:00/wmi_bus/wmi_bus-PNP0C14:00/603E9613-EF25-4338-A3D0-C46177516DB7/backlight/nvidia_wmi_ec_backlight
The brightness control works until i suspend the system (systemctl suspend). After resuming from suspend, brightness is at 100% , and cant be controlled in any way. I tried lts kernel and different kernel and driver versions, never worked. Brightness control always breaks after resume.
System Information:
Razer Blade 18 2023
kernel:6.15.4-arch2-1
nvidia-open: 575.64-5
window manager: niri (wayland)
I discovered this problem happens with suspend-to-ram (deep). Running systemctl suspend with s2idle, is not reproducing the error. But in order to turn my fans off, i need to use deep sleep mode.
I have exactly the same problem, backlight control with nvidia_wmi_ec_backlight works perfectly after the boot but stop working after laptop comes back form deep suspend. It continue working as it should with mem_sleep_default=s2idle kernel option but with this option power draw in sleep is quite significant.
System information:
Razer Blade Advanced 15 2021
Grahpics card: GeForce RTX 3060 Mobile / Max-Q
tried multiple 6.X kernels
tried multiple nvidia dirvers
tried different PRIME profiles
tried different acpi_backlight kernel params
Problem persisted until I’ve set sleep mode to s2idle.