Lenovo Z400 low brightness video driver problem

I have a laptop ideaPad z400 from lenovo that there is a brightness trouble. When it was with windows 10. I were with the same problem, but I could fix easily installing default driver. But now, I've installed ubuntu 16.04 LTS and initially it wasn't any problem but, when I tried to change the brightness, it keep very low.

1 Answer

I have the same laptop and the same problem. Here is the solution I found:

1. Run:

   ls /sys/class/backlight/*/brightness

   You should see:

   /sys/class/backlight/ideapad/brightness/sys/class/backlight/intel_backlight/brightness

2. You need to adjust the first line (adjusting the second line won't do anything). Find the current brightness:

   cat /sys/class/backlight/ideapad/brightness

3. Find the maximum brightness:

   cat /sys/class/backlight/ideapad/max_brightness

4. Adjust it to the desired value, say 15, by:

   echo 15 | sudo tee /sys/class/backlight/ideapad/brightness

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