well… even with acpi_backlight=vender is not entered when booting I have this:
lsmod | grep acer
acer_wmi 27504 0
sparce_keymap 13658 1 acer_wmi
wmi 18744 1 acer_wmi
rfkill 24962 5 acer_wmi, sony_laptop, cfg80211,bluetooth
and
cat /var/log/messages | grep accer_
acer_wmi: Acer Laptop ACPI-WMI Extras
eleven times…