I just beginning new post in new year with Xubuntu fresh installed on X260. A bit of problems around. This post will relate to one problem I found recently.
I cannot bring bring `brightness` back after return from suspend.
1.1. Create this file by command `sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf`
1.2. Add this to file
Option "Backlight" "intel_backlight"
1.3. Restart or may be logout and login
2.1. Edit this file by command `sudo vi /etc/default/grub`
2.2. Modify previous to with this
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux apci_backlight=vendor"
2.3. We should restart, i guess
Finally, I still don't know if it work, but hey, right now it's fine for me