USB to HDMI adapter that works with Ubuntu

Question

I am fairly new to Ubuntu, and am running 20.04. When I was using Windows I had a Startech USB to VGA adapter (https://www.startech.com/en-us/audio-video-products/usb2vgae3) to add 2 external monitors to my laptop. When I switched to Ubuntu, the adapter no longer worked, and there doesn't appear to be an Ubuntu driver for it. I was looking on Amazon and there are some that are only 10 dollars, but the ones that specifically mark they are for Ubuntu are about $50 or more. I don't mind spending that much but if I could get one for less I'd much rather do that. Does anyone know of any relatively cheap USB to HDMI adapters that work with Ubuntu? Any help would be greatly appreciated, thank you!

Answer 1

I have heard that USB-to-video adapters using DisplayLink GPUs have Linux drivers and work well enough. I say "well enough" because USB was not built to support computer displays, it's something of a hack to use USB for this.

If your laptop has a DisplayPort or HDMI output, and I suspect it does as not having a video output on a laptop is rare, then getting an adapter for one of those to VGA should be more stable, give better performance, and not need driver updates with each new OS upgrade. Avoiding the use of VGA would also be wise but I can understand the need to keep using it in some cases. I've used DisplayPort to VGA adapters before and found them inexpensive and "there is no step three" simple to use.

Answer 2

USB video card adapters for Linux Ubuntu

The following info. is up-to-date as of Sept. 2023.

It covers Ubuntu 14.04 and later, through to 20.04, 22.04, and 23.04.

Option 1 [best, if you have USB-C ports]: USB-C to HDMI, DP, etc. adapters

USB-C video cables or adapters are cheap ($15~$30) and easy to find. They can convert USB C to:

1. HDMI
2. DP (Display Port)
3. DVI
4. Component Video
5. VGA
6. etc.

The most common are to HDMI and DP.

Since the video standards are built into the hardware and specifications, they are just plug-and-play, even in Ubuntu, and they take no configuration, no special drivers, and no extra CPU resources.

Here are some examples:

1. USB C to DP cable, $15
2. USB C to DP adapter, $15
3. Amazon search for "usb c to dp adapter"
4. Amazon search for "usb c to HDMI adapter"

Option 2: USB-A to HDMI, DP, etc. DisplayLink adapters

If your computer is older and has no USB-C ports, however, or if all of your video outputs and USB-C ports are taken up on your computer, or if you don't have an output built into your computer that can support 4k at 60Hz, then you can use a special proprietary "DisplayLink" hardware/software solution to give you more monitor output at up to 5k at 60 Hz using standard USB-A 3.0 ports.

DisplayLink has been around since 2007, and is widely supported by a lot of adapters today. Expect it to be ~2.5~10x more expensive ($40~$150) than a comparable USB-C adapter, however. It is now owned by https://www.synaptics.com.

It uses special drivers you have to install on your computer plus a special "DL" DisplayLink hardware chip in the adapter, to force any USB 2.0 or 3.0 port to become an external video card.

Therefore, it also uses extra CPU resources on your computer, unlike the USB-C to video adapters above.

DisplayLink over USB 2.0 is limited to a max resolution of 2048 x 1152, according to here: "Maximum resolution supported: 2048 x 1152". Check the specs of the particular DisplayLink device you buy. It may be lower resolution than this.

DisplayLink over USB 3.0 on the latest DL-6xxx (ex: the latest DL-6950 SoC used by this device here) (on Amazon here for DP and here for HDMI) can support up to 1 video output at 5k 60Hz (5120 x 2880) or 2 simultaneous video outputs at 4k 60Hz (up to 4096 x 2160). That's incredible. I'm sure it's going to use quite a few extra CPU resources to make this happen, however. If you choose HDMI, be sure your version of HDMI supported by the monitor itself can support 4k at 60 Hz. My monitor only supports 4k at 60Hz using the DP cable, not using HDMI.

Read about the different IC generations here, and ensure you know which IC your device you are going to buy has: https://en.wikipedia.org/wiki/DisplayLink#IC_Generations

Common inexpensive ($40) 2k 60Hz adapters like this use the DL-3500 chip and support resolutions up to 2048 x 1152 at 60Hz or 2560 x 1440 (2k, 1440p) at 60Hz. This is likely the adapter I'm going to buy myself. It explicitly says it supports Ubuntu, and reviews confirm this.

Reviews of the $90 Club3D CSV-1477 USB 3.0 Type A to dual 4k 60Hz adapter I mentioned above also state it works for Ubuntu, however. Search the reviews for "Linux" and "Ubuntu".

Driver installation instructions

You should download the latest DisplayLink drivers from Synaptics.com directly here: https://www.synaptics.com/products/displaylink-graphics/downloads/ubuntu. DisplayLink drivers are provided by Synaptics, the maker of the DisplayLink protocol and hardware DL chips, not by the maker of your particular adapter you are looking at, from what I can tell.

Legacy drivers are under the "Legacy Drivers" menu here: https://www.synaptics.com/products/displaylink-graphics/downloads/ubuntu. They go back to Ubuntu 14.04 from 14 Jun. 2017. Looking at the list of all drivers, the DisplayLink binary drivers support Ubuntu 14.04 and newer, including 14.04, 17.04, 17.10, 16.04, 18.04, 20.04, and 22.04, and 23.04. The latest DisplayLink driver supports Ubuntu 20.04, 22.04, and 23.04.

Note: I think you first need to disable Secure Boot in your BIOS for this to work.

For older versions of Ubuntu: How to install DisplayLink software on legacy Ubuntu versions.

For my detailed instructions I wrote myself, see here: Full instructions: installing displaylink-driver on Ubuntu 20.04 (also applies to 22.04 or later).

I have tested my above instructions on Ubuntu 20.04, and the next instructions on Ubuntu 22.04, and they worked:

For Ubuntu 22.04 or later:

# Make this directory if it doesn't exist, and cd into it
mkdir -p ~/Downloads/Install_Files/DisplayLink
cd ~/Downloads/Install_Files/DisplayLink
Download the Ubuntu APT package provided by Synaptics.com, the official
makers of DisplayLink
wget https://www.synaptics.com/sites/default/files/Ubuntu/pool/stable/main/all/synaptics-repository-keyring.deb
Install the DisplayLink APT package keyring
sudo apt install ./synaptics-repository-keyring.deb
Update your APT package cache
sudo apt update
Install the DisplayLink driver provided by Synaptics.com, the official source
sudo apt install displaylink-driver
Reboot.
Now it is plug-and-play. Plug in your DisplayLink adapter and it just works.
It may take up to 5~10 seconds to recognize a monitor.

Official list of DisplayLink adapters

All officially "certified" DisplayLink adapters are listed here: https://www.synaptics.com/products/displaylink-graphics/displaylink-products-list?field_displaylink_category_value=usb_adapters. Make a selection in the "Video Output" dropdown menu to choose HDMI, DisplayPort (DP), etc.

Even if an adapter does not explicitly state it works in Ubuntu, it may still work, so you can always buy it and try it out and leave a review stating whether or not it works in Linux Ubuntu.

The Ubuntu DisplayLink driver for Ubuntu is not open source. They provide the binary only, not the source code. If you'd like to try to extract the separate parts of the binary to make it usable on versions of Linux other than Ubuntu, however, they do provide some "getting started" instructions here: https://support.displaylink.com/knowledgebase/articles/679060.

Good luck. Leave comments and report back your findings. I'd like to hear which DisplayLink adapters people are using in Ubuntu, how well they work, where to buy them, and how much they cost so I can quit doing so much trial-and-error myself.

I'm going to buy an adapter myself and try it out. (Update: done. See below).

What not to use

USB-A to HDMI Devices like this and this may be as little as $13~$25, but they are not DisplayLink compatible, and seem to work on Windows only.

When searching for a DisplayLink device, search the description, reviews, and official Synaptics list of certified DisplayLink devices here: https://www.synaptics.com/products/displaylink-graphics/displaylink-products --> USB Adapters --> "View Products" (direct link here).

My final selection of DisplayLink adapters

I narrowed my selection down to these two:

1. $38, WAVLINK USB 3.0 to HDMI Universal Video Adapter, Displaylink Chips Supports up to 6 Monitor displays, Compatible with Windows, MacOS, Ubuntu 20.04,22.04,LTS, ChromeOS-Upgrade Version - looks like it uses the older DL-3500 chip. Good reviews. Works on Ubuntu. Inexpensive. Up to 2048 x 1152 at 60Hz or 2560 x 1440 (2k, 1440p) at 50Hz.
2. I bought this one: $90, Club3D CSV-1477 USB 3.0 Type A to Dual Display Port 1.2 4K 60Hz External Graphics Video Adapter for Multiple Monitors. There's also the HDMI version: $84, Club3D CSV-1474 USB 3.0 type A to Dual HDMI 2.0 4K 60Hz External Graphics video adapter for multiple Monitors - uses the latest and greatest "DisplayLink DL6950 SOC", which can support 2 simultaneous 4k 60Hz outputs! This one will be much more future-proof, but obviously costs a lot. You may need the DisplayPort version if your 4k monitor only supports 60Hz over DisplayPort, not HDMI, like mine.
   1. You can always buy an HDMI to DP adapter anyway if you want to use the DP version with HDMI. I got a 2-pack of HDMI to DP adapters 4k 30Hz for $10 to use with my older, lower-resolution HDMI monitors on this USB A 3.0 to DP DisplayLink adapter.

My test results of the $90, Club3D CSV-1477 USB 3.0 Type A to Dual Display Port video adapter

Tested in both Ubuntu 20.04 (see my installation instructions here) and Ubuntu 22.04, both with the X window manager.

It works great! I followed my driver installation instructions above, in the terminal. On Ubuntu 22.04, when I ran sudo apt install ./synaptics-repository-keyring.deb, I got this note:

N: Download is performed unsandboxed as root as file '/home/gabriel/Downloads/Install_Files/DisplayLink/synaptics-repository-keyring.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

I don't know what that means exactly, but it had an N: in front, which I think means "Note", not "Warning" or "Error", so I ignored it.

When done with the driver installation instructions, I rebooted, plugged in the Club3D CSV-1477 adapter into a USB A port in a USB-C hub (since my test computer has no USB-A ports; see Note 1 below), and it works! It took quite a few seconds (maybe 5~10 sec) to recognize my monitors I plugged in. I tested a 4k 3840 x 2160 60Hz monitor with a Display Port cable, and a 2K 2560 x 1440 60Hz monitor with an HDMI cable through this DP to HDMI adapter, with both plugged in simultaneously. I also tested an old 1280 x 1024 monitor using an HDMI adapter into the Club3D DisplayPort adapter. It all worked.

There is one bug I noticed, however, where in certain configurations, such as this one, I can move my mouse cursor off the edge of the monitors and into the yellow area here, which I should not be able to do!:

Note 1: Do not use a DisplayLink adapter if you have available USB-C ports. Use a USB-C to DP or to HDMI adapter as described above, instead. I did this just to prove the device works. I'll be using it mostly on a different, older computer which has no free USB-C ports.

CPU usage

I was able to drive a 4k 60Hz monitor over DP and a 2k 60Hz monitor plugged into the same adapter at the same time through an HDMI to DP adapter.

On my super powerful 20-core Dell Precision 5570 laptop running Ubuntu 22.04, I didn't see any noticeable increase in CPU usage. But, this is a very powerful computer.

On my much weaker 8-core Dell Latitude 7490 laptop running Ubuntu 20.04, I saw an increase in CPU usage of a few percent. See images below. But, it was still very usable.

References

1. My Q&A: No 60Hz Refresh Rate option on my 32" 4k external monitor in Ubuntu 20.04
2. This answer: Super User: Hooking up a second monitor using a USB-(Displayport/HDMI/VGA) adapter
3. This answer: Ask Ubuntu: USB to HDMI adapter that works with 20.04

See also

1. My answer: Full instructions: installing displaylink-driver on Ubuntu 20.04 (also applies to 22.04 or later)
2. My article on my personal website where I write about video driver issues in Ubuntu too: Common ways to fix video driver (and related) issues in Linux Ubuntu
3. My answer: Increase timeout when modifying display settings (cannot change monitor layout when using dual-monitor 4k 60Hz DP 1.4 adapter) - solution: restart the computer and then configure the displays with nothing else running.