Please try the kernel @ https://people.canonical.com/~alexhung/LP1894667/
1. remove kernel parameter "acpi_backlight=video" 2. download all deb 3. install kernel by "sudo dpkg -i *.deb" 4. reboot
This should be the same as "acpi_backlight=video" 1. run "ls /sys/class/backlight" 2. verify whether brightness bar works.
Please try the kernel @ https:/ /people. canonical. com/~alexhung/ LP1894667/
1. remove kernel parameter "acpi_backlight =video"
2. download all deb
3. install kernel by "sudo dpkg -i *.deb"
4. reboot
This should be the same as "acpi_backlight =video" backlight"
1. run "ls /sys/class/
2. verify whether brightness bar works.