I have installed Ubuntu 13.04 on Lenovo G700 Laptop.
Screen backlight is going off after boot.
I have tried to fix it with setting
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"in /etc/default/grub file - in that case backlight is set up to 100% and I am not able to change it.
I am looking for a solution when screen is not black after boot and I am able to change the backlight.