On my W520 running ubuntu 16.04 and 367.57 from Ubuntu, both my display port monitor and laptop panel work fine if BIOS startup is configured for nvidia.
But in Optimus mode, Nvidia profile, the laptop panel is not connected.
tim@w520:~$ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 16384 x 16384
LVDS-0 disconnected (normal left inverted right x axis y axis)
DP-0 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 59.95*+
1920x1080 60.00
1680x1050 59.95
1600x1200 60.00
1440x900 59.89
1280x1024 60.02
1280x960 60.00
1280x720 60.00
1024x768 60.00
800x600 60.32
640x480 59.94
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)
In discrete mode, something at startup remove xorg.conf
When booted in optimus, something at startup creates the following xorg.conf:
1 Section "ServerLayout"
2 Identifier "layout"
3 Screen 0 "nvidia"
4 Inactive "intel"
5 EndSection
6
7 Section "Device"
8 Identifier "intel"
9 Driver "modesetting"
10 BusID "PCI:0@0:2:0"
11 Option "AccelMethod" "None"
12 EndSection
13
14 Section "Screen"
15 Identifier "intel"
16 Device "intel"
17 EndSection
18
19 Section "Device"
20 Identifier "nvidia"
21 Driver "nvidia"
22 BusID "PCI:1@0:0:0"
23 Option "ConstrainCursor" "off"
24 EndSection
25
26 Section "Screen"
27 Identifier "nvidia"
28 Device "nvidia"
29 Option "AllowEmptyInitialConfiguration" "on"
30 Option "IgnoreDisplayDevices" "CRT"
31 EndSection
32
When in Optimus mode, the grub menu at boot is different. The fonts are smaller.
During startup, the laptop panel briefly flashes just before the login screen is presented, but the login screen is actually on the external monitor. During the session, the laptop panel just shows a message from near the near the end of the start up process
e.g. a message the /dev/sda6 is clean…
If I ctlr-alt-F1 to access a virtual console, it takes me to the laptop screen, and the external monitor image disappears (but comes back when resuming the X session).
When restarting or shutting down, the ubuntu shutdown ‘splash’ screen appears on the laptop panel, in high resolution. So it seems the intel driver is active on the panel, and for some reason the discrete driver cannot “offload” to it. I guess this means something is wrong with the script-written xorg.conf ?