Comment 19 for bug 1758496

Today I reinstalled my laptop with a Ubuntu 17.10 and the system show the same problem. When the first boot finised I looked for the files on the /sys/class/backlight folder but this folder was empty. I changed /etc/default/grub with GRUB_CMDLINE_LINUX_DEFAULT="nomodeset acpi_backlight=vendor" as Kaihengfeng said. I ran update-grub and reboot, with the same result; /sys/class/backlight folder is empty. The brightness keys don't work. What can I do?

The laptop is working but I have problems when I work on a room with hight level of light.