1. acpi event listener - translate to e internal messages (e_msg)
   (especially button/lid, ac_adaptor, battery, sony/hotkey s1, av mode,
   brightness +, brightness -, sleep, wifi on/off)
   
acpi_listen is a good one (unix socket /var/run/acpid.socket - just cleartext
newline by newline)

2. /proc/acpi/**/**/.../*/brightness controls
   (look at sony and asus - different)
