Chromebook Compatibility with Plugable USB Docking Stations and Video Adapters, 2017

Synopsis

Plugable USB video adapters and USB docking stations can work well with many Chromebooks. In this post we go over the evolution of this support and provide important details broken out in the following categories:

Introduction
Types of DisplayLink chips in our USB docking stations and video adapters
Compatible USB 2.0 devices
Performance Considerations
Compatible USB 3.0 devices
Chrome OS Behavior
Known Issues
Summary
Useful Chromebook tips

Introduction

At Plugable we make extensive use of Google’s cloud-based software services like Gmail and Google Docs so it seems only natural that we are also big fans of Google’s Chrome OS line of Chromebooks and Chromeboxes. Since these devices are designed to be integrated with Google’s services they provide for great value and simplicity.

Not surprisingly, due to their inexpensive and easy to use nature Chromebook use has exploded and in fact many schools now rely on Chromebook solutions rather than a traditional PC or tablet (https://www.nytimes.com/2017/03/02/technology/apple-products-schools-education.html).

As a result, a common question we receive is, do our USB video adapters or docking stations based on DisplayLink technology work well with Chromebooks? We have written in the past about this (http://plugable.com/2015/10/21/chrome-os-usb-docking-stations-displaylink/) but wanted to provide an update with the latest information.

The short answer is that in many cases, yes our USB video adapters and USB docks based on DisplayLink technology can work well with Chromebooks built in 2015 or later but there are important details to consider.

The long answer for those that do what all the details is that the level of support and performance can depend on a few variables, so let’s break those down.

Types of DisplayLink chips in our USB docking stations and video adapters

Our DisplayLink-based products fall into two distinct categories, those that require a USB 2.0 connection and those that require USB 3.0. The key difference here is the type of DisplayLink chip inside the product.

Our USB 2.0 adapters and docks are based on DisplayLink chips that have had drivers written by the open source community for the Linux operating system (in fact our founder Bernie Thompson wrote one version of them himself -> http://git.plugable.com/gitphp/index.php?p=udlfb&a=summary). Chrome OS is based on and in many ways very similar to Linux, so Google was able to integrate these open source drivers into Chrome OS some time ago -> https://bugs.chromium.org/p/chromium/issues/detail?id=238785 This support is available for all Chromebooks which have Intel or ARM processors inside, but not ones with an Nvidia Tegra processor (https://bugs.chromium.org/p/chromium/issues/detail?id=379448#c29)

Compatible USB 2.0 devices

This means that our USB 2.0 video adapters like our UGA-165 (http://plugable.com/products/uga-165/) and our USB 2.0 docking station the UD-PRO8 (http://plugable.com/products/ud-pro8/) should work with just about any Chromebook device. Why do we say ‘should’? Because given the huge number of Chromebooks available (Google has a good reference for most models here -> https://www.chromium.org/chromium-os/developer-information-for-chrome-os-devices) we do not have the ability to test with each and every model (more information on that later on in this post).

Performance Considerations

Beyond just plugging in a device and having it work, another important element to consider is the level of performance. DisplayLink devices are ‘virtual’ graphics adapters in that they rely on a system’s internal CPU and graphics adapter to do the work behind the scenes to drive the attached displays.

As Chrome OS is quite efficient it does not generally require a powerful CPU in order to work well, and as a result many Chromebooks have lower powered processors than their Windows and Mac counterparts. This is a boon in that they can be made cheaper and get exceptional battery life, but when it comes to our adapters some lower powered processors may not provide the same level of performance compared to a system with a more powerful CPU. This drives our recommendation that only Chromebooks made in 2015 or later be used with DisplayLink devices.

Compatible USB 3.0 devices

Moving on to our USB 3.0 DisplayLink products, at this time DisplayLink has released a driver that supports USB 3.0 devices for Linux that is partially open source (http://support.displaylink.com/knowledgebase/articles/1104056-why-has-displaylink-not-released-source-code-for-t) and it has been integrated into Chrome OS (https://bugs.chromium.org/p/chromium/issues/detail?id=572763)

This support is only for Chromebooks based on an Intel or ARM CPU (Nvidia CPU models not supported), and the support again should be universal for all Chromebook devices. Just as before, because given the huge number of Chromebooks available we do not have the ability to test with each and every model.

This means that products based on USB 3.0 DisplayLink chips like our UD-3900 (http://plugable.com/products/ud-3900/) and UGA-3000 (http://plugable.com/products/uga-3000/) should all work on a supported Chromebook. We say ‘should’ again as the same performance considerations mentioned earlier still need to be taken into account, especially for our UD-3900 dock that can add two additional displays. With each additional display more system resources are required, so both the number and resolution of the attached displays can affect the overall performance.

Chrome OS Behavior

In addition to performance considerations, another important thing to consider is how Chromebooks behave when multiple displays are attached. With Windows and Apple Mac systems there are granular settings that control how things behave in terms of waking from sleep, monitor arrangement and what happens with entering docked mode (lid closed with external display, keyboard and mouse attached). .

In Chrome OS, there are very limited options of terms of changing these behaviors so you have to work they way that Google intends. For example, Chromebooks only gained the ability to operate in the so-called ‘dock mode’ in mid to late 2013 (inital announcement here -> https://plus.google.com/u/0/+FrancoisBeaufort/posts/EuJ3ttYSzvp and Issue tracker here -> https://bugs.chromium.org/p/chromium/issues/detail?id=218387 ) which allows for closing the Chromebook lid, disabling the internal display and still allows the externally attached displays to continue to work properly.

Known Issues

In addition to the limited configuration options, there are some unique individual known issues with regard to how our products behave in Chrome OS compared to a Windows system. We pride ourselves on doing our best to provide detail like this up front to help prevent frustration later on, so we have tested our products with a number of Chromebooks and have found the following ‘quirky’ behavior:

  • On certain model Chromebooks (like the Dell Chromebook 13), the ability to ‘Duplicate’ the internal display to the DisplayLink display does not work. ‘Extending’ the internal display to the external DisplayLink display works as expected. UPDATE 8/3/2017 – this has been fixed in the latest development build of Chrome OS, version 61.0.3163.20
  • USB 3.0 DisplayLink devices in most cases will not work after the Chromebook is shut down completely and then started (also known as a ‘cold boot’). The workaround is to unplug the USB 3.0 device and then reconnect it (also known as a ‘hot-plug’). USB 2.0 DisplayLink devices in most cases work as expected in this scenario.
  • In most cases, when closing a Chromebook laptop lid while a DisplayLink device is connected the system will enter ‘Docked mode’. In some instances this message is not displayed when closing the lid.
  • When a DisplayLink device is connected that adds more than one additional display, Chrome OS will indicate that the desktop is being extended but will only provide the name of the first display it recognizes. Both displays still work as expected, this is only a cosmetic omission
  • When waking a Chromebook from sleep, monitors attached to a USB 3.0 DisplayLink device may not always resume as expected. The workaround is to hot-plug the device. USB 2.0 DisplayLink devices in most cases work as expected in this scenario.
  • Another sleep related item, the most reliable trigger to wake a Chrome OS device from sleep when in docked mode is by clicking a button on an external mouse. In many cases pressing a key on an external keyboard will not wake the system from sleep
  • While our devices work well with basic usage applications such as the Chrome browser, video playback performance can vary from excellent to less than ideal depending on the system’s specifications. This is due to the aforementioned reliance of DisplayLink devices on the Chromebook’s internal CPU and graphics adapter, and also drives our recommendation of Chrome OS devices made in 2015 or newer
  • In some instances, a DisplayLink device will not work properly with a Chromebook. It is necessary to ensure that the latest version of Chrome OS is installed (version 56 of this writing) via the directions Google provides here -> https://support.google.com/chromebook/answer/177889?hl=en
    If things are still not working, after backing up any local data try resetting the Chromebook (also known as a PowerWash) -> https://support.google.com/chromebook/answer/183084?hl=en
    If a DisplayLink device does not work with a Chromebook after having reset the system, test the unit temporarily with a Windows system (after installing the necessary driver -> http://plugable.com/drivers/displaylink/ ) to confirm that the DisplayLink device itself is working properly

Summary

In summation, our USB 2.0 and USB 3.0 DisplayLink based graphics adapters can work on most (but not all) Chromebooks released from 2015 onward with the few known quirks mentioned above. Google maintains control over Chrome OS which is a benefit in terms of not having to load any drivers, but also limits Plugable’s ability to make changes. Chrome OS itself is still evolving in terms of the level of configurability of such devices and the consistency of their performance across all the various models of Chromebooks, and we are optimistic things will continue to improve over time. We look forward to your feedback in the comments below, and as always we are here to help should you need direct assistance -> http://plugable.com/support/email/

Useful Chromebook Tips

  • Chromebooks do not have a way to change the time interval before the system will go to sleep. A Chromebook can be forced to go to sleep immediately (even with the lid open) by using the keyboard shortcut -> Search key (the magnifying glass) + Shift key + ‘L’
  • Alternatively, the Search key + ‘L’ key will lock the device, and it will sleep after a few minutes (https://support.google.com/chromebook/answer/2587994)
  • The magnification level of the content shown within the Chrome web browser can be changed using the keyboard shortcut of ‘CTRL’ and the ‘+’ or ‘-’ key
  • The effective screen resolution on an internal Chromebook display can be changed using the keyboard shortcut ‘CTRL’ and ‘SHIFT’ and the ‘+’ or ‘-’ key This only affects the internal Chromebook display and does not affect an external display directly connected to a Chromebook’s built-in secondary video output or a DisplayLink attached display (even when such a display is the only display connected to the system) when the system is running in Docked mode
  • A Chromebook with its lid open and internal display active and an external display connected (either via an internal built-in video output or a DisplayLink device) can be forced to enter ‘Docked Mode’ by holding down the Brightness Down key for a few seconds. This will disable the internal display and leave only the external display, even if the Chromebook lid remains open. To re-enable the internal display, press the Brightness Up key for a few seconds.
  • Chrome OS has many useful keyboard shortcuts, and a quick way to see many of the options available is by pressing ‘CTRL’ and ‘ALT’ and the ‘?’ key. This will display an on-screen representation of the keyboard and the available shortcuts

12 comments on “Chromebook Compatibility with Plugable USB Docking Stations and Video Adapters, 2017”

  1. Jeremy Birch Reply

    I would have thought the Intel based Pro would have better support for a dual display dock over the ARM based Plus. Thanks for idea of using a USB-A dock.

    • Bob Boerner Bob Boerner Reply

      Hi Jeremy,

      The details can be tricky when it comes to Chromebooks with different CPU architectures. The way our UD-3900 works helps circumvent some of these inherent internal physical limitations. For example:

      The ARM-based Samsung Chromebook Plus can only support one display via USB Type-C DisplayPort Alternate mode. In other words, if you use one of our USB-C to DisplayPort cables (http://plugable.com/products/usbc-dp/) connected to the Plus it will work. However, if you connected a second identical cable to the second remaining USB-C port of the laptop it will NOT work. This is apparently a limitation of the internal graphics processor.

      Conversely, if you were to connect two of our USB-C to DisplayPort cables to the Intel-based Asus Chromebook Flip C302 system it will drive two external displays.

      We don’t have a Samsung Chromebook Pro in our lab so we can’t confirm the results would be the same as with the Asus, but that would be my expectation given the similar nature.

      Apologies for the long response.. hopefully that information helps!

      Bob

      • dragon788 Reply

        I have a Samsung Chromebook Pro and tested with the Dell D6000 Universal Dock that uses DisplayLink and it can do 3 simultaneous external displays plus the internal, but in order to use it in that manner you need to attach the displays one at a time to the dock after attaching the dock to the Chromebook. If you allow a little time for it to “settle” you can hook up 3 displays (I’m using 4K displays) and it works quite nicely. I also did the same with the Google Chromebook Pixel LS 2015 and it ran 3 displays quite well, and it was slightly less troublesome with cold plugging the dock with 3 displays already attached, though sometimes I still had to unplug and replug them to get everything happy.

        • dragon788 Reply

          I also discovered with the same dock (Dell D6000 Universal Dock) I am able to fast-charge AND mirror using the DisplayLink Presenter app from my LG G6, though I can only mirror (no charging…yet) from my Google Pixel XL. Since the USB ports work I am also able to attach a keyboard and mouse (though the USB ethernet doesn’t work because it isn’t using a CDC ethernet driver which I believe IS supported by Android). I also discovered that the DisplayLink presenter app will only use a single screen, but the DisplayLink Desktop app (Pre-release status) is able to mirror the phone screen to TWO external displays, which would be great for giving presentations to both sides of a large room or seeing what you are hitting on one screen while giving a demo to an audience.

          Sadly I can’t use the dock through my Mophie charging case for the Pixel XL so I have to get it naked first, but that’s a small price to pay for having a desktop dock, especially since multi-window is quite nice even though the DisplayLink output from Android is limited to 1080p.

          • Bob Boerner Bob Boerner

            Thanks for sharing your results with the Dell docking station, appreciate you taking the time to provide the great detail!

        • Hardy Reply

          Hi

          I have Chromebook pixel 2 ls. I am looking to use it in my office but need to connect two external displays. Do you recommend this and is it very simple? Do you connect display every day or they are connected with the docking station and you just connect your laptop to the docking station?

          Thanks

          Hardy.

    • Bob Boerner Bob Boerner Reply

      To add two monitors to the Samsung Chromebook Plus (hereafter SCP), you could use a combination of our UD-3900 dock (http://plugable.com/products/ud-3900) and our passive USB Type-A to Type-C adapter (http://plugable.com/products/usbc-af3/) One thing to keep in mind is that the SCP has an ARM architecture processor that may not perform as well as a Chromebook with an Intel architecture processor (I speak to this in general in the body of the blog post). If you elect to proceed with your purchase and find that the dock does not meet your needs or expectations, we do offer a 30-day no-hassle return policy for all products sold by Plugable Technologies and fulfilled by Amazon.

  2. Jeff Kirk Reply

    The Samsung Chromebook Plus (SCP) will use one Alt-mode adapter. It will not use two, even if they are plugged in to each side (each Type-C). However, if you plug the Plugable USB 3.0 4K HDMI Adapter into your Type-C docking hub, both the Alt-mode device and Display link device are detected and you get three displays!!! Internal and two external, and all are visible in the display settings UI. The display link monitor is good for 1080P, unlike Chromecast output. Cursor is responsive. No lag. The last keyboard stokes don’t flush to the display. Any update will flush them. Maybe I need an analog clock app with a second hand to force the flush.

    All in all, very pleased. SCP makes a great visual work center, connected to two Vizio 40in TV displays. Had to block the TV IP ports to avoid conflicts from the remotes, but it works.

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