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Here is a case I bring my Thinkpad T420 notebook to office place and there was plenty of monitors free but all were quite modern and had support only for Display Port / DVI and HDMI (High Definition Multimedia Interface), e.g. there was no Monitor to support regular VGA port …
I've conntected my Debian 9 Stretch Linux with a DisplayPort cable to one of the LG monitors but the external monitor video screen did not raised the screen kept black just like nothing is connected to it.
So i did a quick research online to see whether and how I can make the display port on Lenovo thinkpad t420 work with Linux after consulting few resources online e.g. Hacksr Display Port on Thinkpad T420 and Nvidia Optimus this post in Ubuntu Forums as well as the official documentation about DisplayPort and Linux on Thinkpad's official documentation ThinkWiki it turned out the T420 Thinkpads have issues with Displayport and Linux and the only solution proposed was to use the second Nvidia Optimus card instead of the integrated display adapter, I however am not sure whether my notebook have this Nvidia at all and did not have time for too much hacking to make it work.
I decided to take a more simple approach and try to use the good old school VGA port protocol with one of the 2 ThinkCentre Edge m93z stationsthat were hanging around in the office, in case you never heard of ThinkCentre Edge this is (an integrated computer and monitor in a thin display a kind of cheap PC alternative from Lenovo to iMacs (all in one Macintosh Desktop computer) .
I saw some skeptical looks from colleagues but I with my usual stubborness gave it a try and after a bit of quick research I got it working on Linux ! 🙂
If you're wondering whether THINKCENTRE Edge can be used with VGA port as External Display to a Linux powered Laptop the Answer is YES !!! 🙂
To make it working,
All you have to do it is configure it as External display from ThinkCentre (OSD) display menu.
But wait the joy was not so full, even though the ThinkCentre displayed my GNOME FlashBack background picture on its screen it did not show my actual GNOME Menus (Application, Places and Desktop) just like shown in below screenshot ..
I could see fine the ThinkCentre monitor showing normally in xrandr command which is the tool to always check first if you're new on Linux and want to check settings regarding your Notebook display settings / Desktop PC exnternal display settings on Linux , the output of xrandr is below.
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 4096 x 4096 LVDS1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1920x1200 60.0 + 1600x1200 60.0 1680x1050 60.0 1280x1024 76.0 75.0 72.0 60.0 1440x900 75.0 59.9 1152x864 75.0 1024x768 60.0*+ 800x600 60.3 56.2 640x480 59.9 VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 519mm x 324mm 1920x1200 60.0 + 1600x1200 60.0 1680x1050 60.0 1280x1024 76.0 75.0 72.0 60.0 1440x900 75.0 59.9 1152x864 75.0 1024x768 75.1 70.1 60.0* 832x624 74.6 800x600 72.2 75.0 60.3 640x480 72.8 75.0 66.7 60.0 720x400 70.1
I also gave a try to arandr which is a simple GUI interface to xrandr, i.e.:
root@jericho:~# apt-get install –yes -qq arandr
Unfortunately trying to turn on / off the VGA monitor shown in above screenshot using arandr and saving did not produced any positive results, as the ThinkCentre Edge used as external monitorkept being showing only my Debian Linux background.
During my attempts to make it working I stumbled upon driconf a configuration applet program for Direct Rendering Infrastructure (DRI).
I also gave a try to default gnome-control-center Monitor settings tool but I couldn't turn off the notebook display in order to make the ThinkCentre Edge my primary display.
Finally after some more investigation online, I found how to switch on my Notebook display by running below xrandr command
xrandr –output LVDS-1 –off
Just in case if you need to re-enable (on) the LVDS-1 use
xrandr -d :0 –output LVDS –auto