Can I get external monitors connected to docking station to work with my Lenovo T420s?
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I have the same problem, and I have done some research and partially solved it. However, I am still working on a complete solution.
The hardware:
- Thinkpad T420s with Nvidia 4200M + Intel HD 3000 graphics
- Thinkpad dock.
The symptom:
- T420s can't recognize the external display connecting to any DVI port on the dock.
- It can recognize the external display through VGA port on the dock. However, the quality is poor.
The root cause:
- T420s has Nvidia card connecting to DVI port while Intel card to VGA port on the dock.
- Unlike Win 7, Ubuntu can't switch between Nvidia card and Intel card. By default, only Intel card is being used.
The solution:
- Put T420s to dock and connect the external display to DVI port.
- Goto BIOS, find "Display", change the configuration to "Discrete Card" and "Disable Nvidia Optimus". Now T420s is forced to use Nvidia card.
- Download and install Nvidia driver for Linux. Google the detailed instructions.
- After the installation, Do "sudo nvidia-settings".
- In the pop-up window, "X Server Display Configuration", Click "Detect Displays". You will be able to see the external display now.
- In the same page, change Configuration to "TwinView", Resolution "Auto" or the native resolution of T420s, say, 1600x900.
- Click "Apply", you will be able to see the external display desktop.
- Click "Save to X Configuration File". A new /etc/X11/xorg.conf will be created.
Remaining Issues to Resolve
There are still a couple of issues. I'm still working on it. Most likely, a proper xorg.conf will solve them.
Hope it helps.
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Author by
David LeBauer
Updated on September 18, 2022Comments
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David LeBauer over 1 year
I have a new Lenovo T420s with Nvidia 4200M + Intel HD 3000 graphics cards. When I attach the laptop and monitors to the docking station, nothing happens - the monitors are not recognized.
What I have tried that did not work:
- all variations of the Display settings in BIOS (Dedicated, Optimus, Integrated)
- installing proprietary drivers
- then, I installed nvidia settings and ran
sudo nvidia-xconfig
after which I had to remove/etc/X11/xorg-config
before x would work again.
- then, I installed nvidia settings and ran
- using a vga cord (ubuntu recognized monitor but did not send any video there)
- removing proprietary Nvidia drivers
- reinstalling Ubuntu
- using Unity 2D and xfce
I have googled quite a bit with little success. I have been told by IT to install windows 7 and use Ubuntu as a VM. What are my other options?
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David LeBauer over 11 yearshave you had any luck finding a complete solution?