I'm on a Dell XPS 15z. I detail below other attempts (all pretty much taken from this thread but unsuccessful for my setup); instead, what works for me is to (1) change in /etc/default/grub the variable GRUB_CMDLINE_LINUX_DEFAULT to "acpi_backlight=vendor dell_laptop.backlight=0 quiet splash", i.e., adding the entire part beginning "acpi_backlight..." ahead of "quiet splash", as suggested in
https://wiki.ubuntu.com/HardwareSupport/Machines/Laptops/Dell/XPS/15z (thanks). What also worked was (2) replace the Display Manager lightdm with gdm, i.e., in a terminal do sudo apt-get install gdm and then select gdm, although obviously that's not a fix for a lightdm problem. [Alternatively, "sudo dpkg-reconfigure gdm" if you're, luckily, already running lightdm or some other DM.] Trials that failed for me: A. In /etc/init/lighdm.conf Add line "sleep 10" just before line "exec lightdm" Add flag "-d" to "exec lightdm" Add line "and stopped udevtrigger" just after line "and started dbus" Add line "respawn" right before "emits login-session start" (whether in combination or singly). B. In a terminal "sudo restart lightdm" or "sudo service lightdm restart" or "sudo service lightdm --full-restart". -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/969489 Title: lightdm tries (and fails) to start too early? To manage notifications about this bug go to: https://bugs.launchpad.net/upstart/+bug/969489/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
