Hi all, I noticed a surprising behavior regarding screen brightness management on a laptop running OpenBSD (ThinkPad T14 Gen2, OpenBSD 7.6):
Even with apmd(8) stopped and disabled, the screen brightness is automatically reset to 100% whenever the AC power is connected or disconnected. My default brightness is set to 15 (via /etc/wsconsctl.conf), and this gets overridden every time the power state changes. After some investigation, it appears that the cause might be in the kernel, specifically in acpivout(4), where acpivout_notify() sets brightness to 100 on certain power events. Would it be possible (or reasonable) to make this behavior optional – for example via a sysctl, or by simply preserving the user's brightness setting unless explicitly changed? I understand OpenBSD favors simple and predictable design, so if this is intentional, I'd just like to understand the rationale behind it. Thank you for your work and your time. Best regards, Tomas Rippl
