I normally have the brightness set to max or near max (at least 80%), but each time I reboot or wake from sleep, the display brightness resets to minimum.

There are other similar questions here, but the proposed solutions all refer to files in acpi_video0/ which I do not have. The only thing in my /sys/class/backlight directly is a shortcut to an intel_backlight directory with an absurdly long path name. From the files within this directory, I gather that the brightness level ranges from 0 to 4882 (so nothing close to what I've seen posted in other questions, where the max is 8 or 10).


I have the N56VZ-S4016H model and also a couple of problems with backlights (and the ethernet driver). I found two options for backlight problems:

  • install xbacklight and add it to your autostart configuration (xbacklight -set 100 for 100% level) - the Fn+F5/F6 keys will still not work, not even recognised as key presses.
  • use acpi_osi= as a boot parameter in grub. As far as I can see on my model, it fixes all FN keys: add acpi_osi= after splash, it'll look like this:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="

    don't forget sudo update-grub

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