Display brightness control

display.brightnessHands-on · observedHigh confidence

How it tests

Picks a backlight device (firmware type first, then platform, then raw), steps it to about 15 % and to full, 1.4 s each, puts it back, and asks whether the screen dimmed and brightened. The driver's read-back goes in the evidence.

How it decides

Supported: every step seen. Partial: only some steps. Failed: no change seen, no backlight device, or the kernel refuses the write.

How sure it is

You see the panel, so a “no” is reliable. A “yes” is your plain answer, one of the few that can give a pass.

On a real Mac

On a MacBook Air (13-inch, Mid 2012): acpi_video0, every step seen, 3 of 3 levels read back.

What could mislead it

Could pass when it shouldn'tThe firmware device (acpi_video0) works but Omarchy's brightness keys drive another (intel_backlight), or the reverse.
Could pass when it shouldn'tThe tester answers “yes” without watching.
Could fail when it shouldn'tAn iMac without a backlight class device fails though the panel works.