I have acer aspire 5734z with gma 4500 running archlinux. best solution for me is adding GRUB_CMDLINE_LINUX="acpi_osi=Linux" to /etc/default/grub then update grub. still starts dark but brightness keys work. it is kernel issue not the operating system. See here https://lkml.org/lkml/2011/4/5/172 I think "acpi_osi=" works also
I have acer aspire 5734z with gma 4500 running archlinux. best solution for me is adding GRUB_CMDLINE_ LINUX=" acpi_osi= Linux" to /etc/default/grub then update grub. still starts dark but brightness keys work. it is kernel issue not the operating system. See here https:/ /lkml.org/ lkml/2011/ 4/5/172 I think "acpi_osi=" works also