I believe that the laptop uses Hybrid Graphics (AMD + Intel). Hybrid Graphics are problematic in Linux right now, there's nothing that will work 100% for everyone. I recommend disabling the discrete AMD GPU so that it won't chew up your battery life.
To resolve the brightness button issue you're having, follow these steps:
- Open up a terminal (Ctrl + Alt + T)
Type in the command:
gksudo gedit /etc/default/grub
In that file you will find a line like this GRUB_CMDLINE_LINUX_DEFAULT="quiet splash". Append the following after splash acpi_backlight=vendor so the line looks like:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
And save the file and exit gedit.
Now in the terminal execute the following command:
Now reboot and your brightness buttons should work.
You probably have the discrete card running and chewing up your battery. If so, you can disable it via vgaswitcheroo. Type this command in a terminal:
echo OFF > /sys/kernel/debug/vgaswitcheroo/switch
To make the changes to persist after reboot you can put this command in your /etc/rc.local so that it executes at every bootup, in a terminal execute:
At the end of the file before the exit 0 line, paste the command echo OFF > /sys/kernel/debug/vgaswitcheroo/switch, save and you're good to go now the discrete GPU will be disabled at boot.
For more information see HybridGraphics