Connect a Second Monitor to Linux Mint with a USB to HDMI Adapter

Having a second or even a third monitor attached to your PC gives a helpful increase in screen space. Being able to have more windows and applications visible at once improves productivity and can reduce the stress of computer usage.

Generally, the number of screens is limited by the number of PC interfaces. Especially for laptops, which often have fewer ports than desktop/tower systems. Fortunately, the number of monitor ports can be increased by the addition of a simple adapter. For Windows users it’s easy. For Linux users, well it is quite easy too, as this article explains.

USB to HDMI Adapter

A adapter can change a spare USB port into HDMI. I bought this Cable Matters USB 3.0 to HDMI Adapter from Amazon for ¬£51. Although it is entitled “…for Windows“, it operates fine with Linux. I proceeded as below to install the driver and get it working. By the way I am using Linux Mint 20.1 MATE on a laptop made by MSI, model cx61.

The adapter model number is 103046.

Physical Installation

Start by physically installing the adapter. Disconnecting your monitor from HDMI, if connected, and reconnected it to a USB 3 port, via the interface adapter.

Download the DisplayLink Driver

Download the Displaylink (who make the adapter’s chipset) driver from here:
https://www.synaptics.com/node/3146?filetype=exe. Click the “Accept” button and save the file, which will be saved as “DisplayLink USB Graphics Software for Ubuntu5.3.1-EXE.zip”. Note: By the time you read this article, which was written in April 2021, the version and name of the file might have changed slightly, as might the download URL. If so, it should be quite easy to find it with a Google search of “Linux driver for Displaylink HDMI adapter”, or similar.

Driver Installation

Unpack the zip file, which will reveal a single runnable file. Run it. Example commands:

# unzip "DisplayLink USB Graphics Software for Ubuntu5.3.1-EXE.zip"
# ./displaylink-driver-5.3.1.34.run
Verifying archive integrity… 100% All good.
Uncompressing DisplayLink Linux Driver 5.3.1.34 100%
DisplayLink Linux Software 5.3.1.34 install script called:
Distribution discovered: Linux Mint 20.1
...

Enter “y” in answer to the question “Do you want to continue? [Y/n]”

Much more stuff is printed at this point. Packages are installed from standard repositories, including dkms and libdrm-dev. A kernel module is built (evdi.ko). Finally a message appears:

Installation complete!

Reboot your system to make sure the driver is properly picked up.

Configure Monitors

If you have more than one monitor connected, it will probably be necessary to configure the layout. I am running Linux 20.1 “MATE” version. So I used the (rather flaky) “Monitors” graphical application to arrange my monitors and desktop as desired. If you are using Mint Cinnamon, or even another distribution altogether, there will be an equivalent app, but I am not sure what it is called.

Performance Testing

An HP Pavillion 23 XI monitor was connected over the adapter, at a resolution of 1920×1080. There was no noticeable decline in performance versus a direct HDMI connection. I’m not a gamer and use the monitor for normal desktop work, such as web surfing and business applications.

Little CPU load was imposed by the adapter. For example, watching an HD video on the relevant screen, or just moving a window backwards and forwards (fully rendered), brought a “DisplayLinkManager” application to use 140% of CPU. On my powerful but ageing laptop (CPU: i7-4702 MQ, a fourth generation i7 with 4 cores/8 threads), that is engaging less than 1.5 out of 8 available cores. In fact watching the HD video usually imposed about 60% of one CPU.

I then switched the adapter to a new Dell U2719D 27″ Widescreen monitor, at a resolution of 2560 x 1440. That’s 2K, and the maximum resolution of the USB adapter. Again, there was no noticeable degradation in performance in normal “office” use. And watching this test 2K video stressed the CPU to, again, about 140% of one thread or less.

Not sure what difference it makes, but the laptop graphics card is an Nvidia GeForce GT 740M.

Performance should therefore not be an issue, except perhaps in base model PCs with 2 threads or less.

New Kernels

It might be expected that the driver would need to be rebuilt with every new kernel installed on the PC. This appeared not to be the case. A kernel install did not appear to trigger a rebuild.

Other Linux Variants

This DisaplayLink driver, is likely to work on other Debian based distros, for example Ubuntu. Red Hat/Fedora based systems might need a slightly different approach.

Conclusion

Being able to connect a monitor via USB obviously increases the number of monitors you can have, and provides a useful upgrade path where existing ports are limited. By adding a USB 3 hub, it should be possible to connect many screens to a single laptop.

I didn’t use a hub, but had three monitors connected and running fine: one via the USB to HDMI adapter, another directly to the laptop’s HDMI port, and third, older monitor to the VGA port. All were different resolutions, and all worked fine together.

Disclaimer

This article is simply a record of a procedure carried out on my laptop. No guarantee or assurance of any kind is provided that the same procedure will work for you.

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