my /etc/lightdm/lightdm.conf file [SeatDefaults]user-session=ubuntugreeter-session=unity-greeterallow-guest=falsedisplay-setup-script=xrandr --newmode 2560x1440 220.812 2560 2608 2640 2720 1440 1443 1448 1478 -hsync -vsync  && xrandr --addmode HDMI1 2560x1440 && xrandr --output HDMI1 --rotate rightWhen I start the computer, there is a black blank screen as the x server is stopped due to an error. When I run the xrandr command normally in terminal when logged in, it does work.Errors in  ~/.xsession-errors.oldopenConnection: connect: No such file or directorycannot connect to brltty at :0upstart: window-stack-bridge main process (2057) killed by HUP signalupstart: bamfdaemon main process (2115) killed by TERM signalupstart: hud main process (2186) killed by HUP signalupstart: unity-settings-daemon main process (2188) killed by HUP signalupstart: gnome-session (Unity) main process (2195) killed by HUP signalupstart: unity-panel-service main process (2202) killed by HUP signalupstart: indicator-messages main process (2231) killed by HUP signalupstart: indicator-bluetooth main process (2232) killed by TERM signalupstart: indicator-power main process (2233) killed by TERM signalupstart: indicator-datetime main process (2234) killed by TERM signalupstart: indicator-keyboard main process (2235) killed by HUP signalupstart: indicator-sound main process (2236) killed by HUP signalupstart: indicator-printers main process (2239) killed by TERM signalupstart: indicator-session main process (2240) killed by TERM signalupstart: indicator-application main process (2249) killed by TERM signalupstart: indicator-application pre-stop process (3254) killed by HUP signalupstart: unity7 main process (2277) terminated with status 1
xrandr command does not work in lightdm.conf
x11;xrandr