AMDGPU: Incorrect initial brightness state on Radeon 780M despite correct software value

Hardware:

• CPU: AMD Ryzen 7 8840HS
• GPU: AMD Radeon 780M (integrated graphics)
• Display: Zenbook 14 (2024) with 1920x1200 display
• Kernel: 6.9.3-76060903-generic

Issue Description: The display brightness is set to maximum on boot despite the software brightness value being set to 15. This mismatch between reported and actual brightness only occurs during initial boot. Once any manual brightness adjustment is made, the hardware and software values sync correctly.

Steps to Reproduce:

1. Boot the system

2. Check initial brightness value: $ cat /sys/class/backlight/amdgpu_bl1/brightness Output: 15 Actual display: Maximum brightness

3. Set the same brightness value manually: $ echo 15 | sudo tee /sys/class/backlight/amdgpu_bl1/brightness Result: Display correctly dims to low brightness level

Additional Information:

• Issue occurs on both Pop!_OS 22.04 and Linux Mint 22.1
• Manual brightness control works perfectly after first adjustment
• Attempted fixes (systemd service, kernel parameters) don't resolve the issue
• Issue persists across reboots

added DC Phoenix / Hawk Point labels

I'm pretty sure we had a fix for this already in 6.12, can you please try an upstream kernel?

drm/amd/display: Fix brightness level not retained over reboot · torvalds/linux@4f26c95

marked this issue as related to #3655 (closed)

Yes, thank you for the advice. I have installed kernel version 6.12.13-061213-generic, as you instructed. The brightness does show correct level of brightness on boot using this kernel version. Thank you and sorry for submitting duplicate issue.

closed