Simply add the option acpi_osi=Linux to your GRUB commandline.
To make this a permanent solution you can edit the file /etc/default/grub and append the option to the line
GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash”
so that it looks like this:
GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_osi=Linux”
Don’t forget to run update-grub2 to regenerate the grub menu.