It seems that even with macOS 12.1, iBoot will insist to set backlight brightness to an very dim value (possibly because the backlight-nits nvram variable cannot be altered?). So it's important (to me) to reimplement backlight brightness support using the new DCP driver, so I can at least set it initially; setting it dynamically may also be useful to people.
The good news is this appears to work using the current driver and the /sys/kernel/debug/dcp/command interface. The bad news is the relevant command currently has to be constructed by hand (I use echo -ne '253A\x08\x00\x00\x00\x04\x00\x00\x00...'
It seems that even with macOS 12.1, iBoot will insist to set backlight brightness to an very dim value (possibly because the
backlight-nitsnvram variable cannot be altered?). So it's important (to me) to reimplement backlight brightness support using the new DCP driver, so I can at least set it initially; setting it dynamically may also be useful to people.The good news is this appears to work using the current driver and the
/sys/kernel/debug/dcp/commandinterface. The bad news is the relevant command currently has to be constructed by hand (I useecho -ne '253A\x08\x00\x00\x00\x04\x00\x00\x00...'