How to attach 3, or 4 screens to T540p Lenovo laptop
This howto should work for any computer with the same graphics card.
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor DRAM Controller (rev 06)
00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller (rev 06)
The computer has some graphics outputs and some more are on the docking station. I have tried several combinations
and everything worked including one screen connected to VGA on the laptop and another to DVI on the docking station.
But there is a limitation. The maximum are two non-DisplayPort screens and three screens at all (including the internal
screen which is DP, so you can add two random screens freely).
If you're thinking about some convertor from DP to yur older screen, you should know, that the convertor must
be active (big, expensiver, powered up by USB probably). Passive convertor will work as non-DP screen.
What I have used:
internal + VGA + HDMI on the dock
There are differences between Xserver and xrandr versions, so I'm going to describe it for Fedora 20 and Fedora 24.
You can play with xrandr for other distributions.
F20: (I hope I have reconstructed it right, because I don't want to downgrade now :-))
xrandr --output DP-1-3 --off
xrandr --output DP-1-2 --off
xrandr --output eDP-0 --left-of DP-1-2
xrandr --output DP-1-3 --left-of DP-1-2
There is no need to specify screen resolutions. It used the biggest available for the screen. 1920x1080 and 1280x1024.
F24: xorg-server 1.18.4, xrandr program version 1.5.0, Server reports RandR version 1.5
xrandr --output DP2-1 --off
xrandr --output DP2-2 --off
xrandr --output DP2-2 --mode 1920x1080 --right-of eDP1
xrandr --output DP2-1 --mode 1920x1080 --right-of DP2-2
Outputs has different names (hw is plugged exactly the same) and it's not working without explicit --mode.
internal + VGA + HDMI on the dock + USB
I have used USB graphics card Displaylink with the DL-165 chip. It isn't a graphics card actually - jist a piece of RAM ,
decompressor and the CRTC (have you seen error message about not available CRTC if you have tried to add another screen?).
It works on F24, but it has crashed Xserver on F20.
Put the screen to the card, card to USB (it will detect screen's available resolutions) and run one command (or add it to
commands for F24):
xrandr --output DVI-I-1 --mode 1280x1024 --left-of eDP1
The card can even play a 1280x1024 video, but it wasn't Hollywood movie with lots of explosions. All compressed data must
go through one 480 Mbit/s USB 2.0.
I'm sorry for my English. It isn't my first language and - considering the fact I'm learning it more than quarter of century
and it looks like this still - it will by my only foreign languge forever.