Hello,
I’ve been trying to get native brightness control working on an Apple iMac14,3 with NVIDIA graphics (and the nouveau driver). Using the acpi_backlight=video kernel parameter I have successfully exposed this to /sys/class/backlight/acpi_video0 and I’m able to manually control it by writing to the brightness file there.
Unfortunately regardless of what I’ve tried, I haven’t been able to get GNOME to display its native brightness controls for it. Interestingly enough, my iMac18,2 with AMD graphics provides the exact same acpi_video0 file in the sysfs and GNOME picks it up perfectly fine, so I’m confused as to what the difference might be.
Both are running a fresh install of Ubuntu 26.04 with GNOME 50. What could be causing this?