Screen fully dimmed when battery is low

Hi,
My laptop is ThinkBook 16 G6 ABP with AMD Ryzen 7 7730U. I installed Debian 12 (trixie) and I'm having a strange issue, my screen dims fully when battery is low.

Symptoms:

The laptop display dims to almost unreadable levels under two conditions:
- At 20% battery level with no external monitor
- At 50% battery level when an external monitor is connected

Key observations:

- Display is not completely off (window movements are visible at very dim levels)
- Brightness controls don't work when in this state
- System shows 'brightness'=123 but 'actual_brightness'=0 (at /sys/class/backlight/amdgpu_bl0/ folder)
- Plugging in AC power immediately restores normal brightness
- The issue appears in both Power Saver and Balanced power profiles
- This issue was not present on Pop OS (both 22.04 LTS and 24.04 alpha) on the same hardware

Technical Details:

- The system is using amdgpu driver for display
- Backlight is controlled via amdgpu_bl0
- There's a discrepancy between system-set brightness and actual brightness values
- Power profiles available: performance, balanced, power-saver. And issue persists across different power profiles

Can you please help me resolve this issue?

Statistics: Posted by alperyilmaz — 2024-12-30 12:28 — Replies 2 — Views 63

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