Category Archives: UGA-2K-A

DisplayLink USB 2.0 Graphics Adapters on Linux – 2014 Edition

IMG_20140306_164523A little over a year ago I wrote a blog post discussing the state of USB Graphics on Linux systems, specifically, Fedora 18. What follows is an update on the situation, looking at both Fedora 20 and Ubuntu 13.10, and examining how far we have come, and how far we still have to go.

The short story

Multi-monitor on Linux, especially with multiple graphics cards and USB graphics adapters, remains problematic. You can find many distros and configurations where it just won’t work. We’d recommend staying away unless you’re an advanced Linux user who is willing to play with different distros, install optional components and do hand configuration. Unfortunately, it’s just not plug and play yet today, as it is on Windows.

The long story

That said, it is possible to get things working in limited scenarios for USB 2.0 generation DisplayLink-based adapters. We used all Plugable products in the tests for this post. Our test systems included Intel, Nvidia, and AMD primary graphics adapters. For Nvidia and AMD, we tested both the open-source and proprietary drivers.

Intel is the most compatible, providing decent results under all configurations.
Nvidia graphics cards, when running the open source nouveau driver, only work in Multi-Seat mode. Attempting multi-monitor setup with a DisplayLink adapter and an Nvidia graphics card results in garbage graphics being displayed on your DisplayLink-attached monitor. The Nvidia proprietary drivers do not work under any scenario.
The AMD open-source drivers work under both multi-seat and multi-monitor setups, but the performance, at least in our tests, is significantly worse than with the Intel drivers.
The AMD proprietary drivers are unavailable in any easy to install package under Fedora 20, but we installed them in Ubuntu, and were unable to get any results, they simply do not work with DisplayLink graphics.

Fedora 20

Fedora has always provided the best support for DisplayLink graphics on Linux. We noticed some regressions on Fedora 19, but these have largely been resolved in Fedora 20. There isn’t much new to report.

You should be able to connect one of our docking stations and create a plug-and-play multi-seat setup, or connect one of our display adapters, and expand your desktop to an extra monitor using the Arandr utility, or something similar.

Ubuntu 13.10

Ubuntu still has several issues with DisplayLink graphics, and they do not work out of the box.

In order to enable DisplayLink adapters to work on Ubuntu, one must download the latest Mainline Kernel build from the Ubuntu Kernel PPA, install it, and then reboot with that kernel. Once this is done, DisplayLink graphics adapters will work in multi-monitor mode. Simply enable them from System Settings like you would enable any extra monitor attached to your PC.

A step-by-step guide to accomplish this will not be provided because switching away from your distro-provided kernel is something only expert users should attempt.

It should be noted that the reason this is necessary is due to the Ubuntu team making some changes to the kernel that they ship with Ubuntu, resulting in broken DisplayLink graphics support. A bug report has been submitted, here.

You can also keep track of the USB Graphics situation under Ubuntu in this blueprint.

Performance

Performance continues to be an issue with DisplayLink on Linux. Using a composited window manger(Gnome 3, Unity, Cinnamon, etc) will result in poor performance across all of your displays. Compositing re-renders far more pixels than non-compositing desktops. When you’re just going through a GPU, you’ll only notice battery loss. But when all those pixels have to get processed by the CPU and sent over USB, it’s a huge hit.

Switching to a lighter-weight window manager or desktop environment (XFCE, LMDE, Mate, etc) results in a quite usable setup, provided your main display adapter is a recent Intel chip.

Unfortunately, due to the discontinuation of Gnome 3′s fallback mode, that is no longer an option for improved performance.

Other Outstanding Bugs

Besides the issues I mentioned above, there’s still a few other problems.

When rebooting your Linux computer, or simply logging out and back in, your USB-attached displays will not always come back without having to disconnect and reconnect them.

Changing the location of your DisplayLink screens in your virtual desktop can sometimes cause strange issues (like only half of the monitor rendering). Toggling the screen on and off inside of your Display management UI usually solves this.

Nvidia’s and AMD’s proprietary drivers are still entirely incompatible with DisplayLink graphics on Linux.

Conclusion

We hope this background helps. We don’t recommend or support USB graphics on Linux yet, because of the problems above — but if you do have questions, please feel free to comment below. We want to get as much information out as possible about what works and doesn’t, so things can improve here. There’s no reason Linux can’t have the same or better multi-monitor support as any other platform in time!

If you are an Open Source Kernel or User-Space developer that would like to help improve this situation, we’d like to point you to our Plugable Open Source Hardware Samples Program where you may sign up to receive free sample hardware to help on your development efforts.

DisplayLink Releases Version 2.1 Driver for Mac OS X

There have been many multi-monitor regressions from OS X 10.8.5 to 10.9, and USB graphics has been significantly impacted.

Part of the confusion is not knowing which new problems are fixable by DisplayLink and which ones will require waiting for the next point releases by Apple.

We have a clearer picture of that now with DisplayLink’s version 2.1 driver final release. A number of things are greatly improved, including a fix for the new performance problems on 10.9 — performance is now back up to 10.8.5 levels.

However, we’re still recommending that anyone on 10.8.5 with a multiple-monitor setup, stay there until Apple has a chance to get out some point releases. In particular, multi-monitor setups of many types are losing configuration, often on sleep. And virtual graphics drivers like DisplayLink aren’t working for 2 or more displays. Both of these problems are new for 10.9.

See the comments on our original 10.9 multi-mon post for different problems reported by customers with DisplayLink and non-DisplayLink hardware. DisplayLink lists the 10.9 issues they’re aware of in the DisplayLink KB article for OS X 10.9.

So, progress .. but for most 3+ monitor users, 10.9 is still not workable. So we can’t recommend any of our Plugable brand products with DisplayLink for Mac, unfortunately. We’ll update as Apple and DisplayLink put out additional point releases.

Feel free to post your experiences in the comments below — it helps everyone to have the behaviors be known. Thanks!

Before You Upgrade To Mac OS X 10.9 (“Mavericks”)

Good news: Mac OS X 10.9 is available today and for the first time, it’s a free update, so app and hardware developers will be able to start counting on Mac hardware running the latest software in general (kinda like the iOS world).

Bad News: Mac OS X versions have historically broken some percentage of 3rd party hardware, and OS X 10.9 appears to have a particularly big impact. Many hardware devices will need updated drivers for 10.9, either because the older drivers simply don’t work at all, or because they work but with new problems.

If you can, it may be better to wait for the adventurous to forge ahead and report their findings on 10.9, before taking the upgrade.

DisplayLink Based USB Products

Users with DisplayLink-based USB Docking Stations and Graphics Adapters should avoid updating to 10.9, if at all possible. See here for details.

DisplayLink-based USB devices that work well on 10.8.5 (up to 4 additional USB displays) will be broken for most uses by the 10.9 update. In particular, 2+ USB displays or any HDMI-attached displays (even non-DisplayLink) don’t work reliably because of screen configuration issues.

We don’t know when this is going to be fixed — but evidence is it will require fixes both from Apple and DisplayLink, so that will take a significant amount of time.

If you are able to stay on 10.8.5, or if you only need a single USB attached DVI/VGA monitor on 10.9, use
DisplayLink’s latest 2.1 Beta drivers.

USB Network Adapters


Mac OS X 10.9 (and 10.8.5) includes support for both the AX88772 chipset and the AX88178 chipsets in our USB 2.0 USB Ethernet adapters, and UD-160-A docking station. For these chips, we recommend first uninstalling any ASIX drivers and repairing disk permissions before upgrade to 10.9 (relying on your built-in net connection), and just plugging in to use the Apple drivers after upgrade.


For our USB 3.0 Gigabit Ethernet adapter, an updated ASIX driver is required. In addition to Mavericks support, compatibility issues with Android File Transfer seem to be resolved. That said, we’re seeing reports of some new problems with 10.9 and would recommend caution. For those who have already updated to 10.9, the compatible driver is available at:
the latest ASIX driver version to get 10.9 compatibility. Note that this driver does not yet have the new 10.9 signature, so you’ll also need to click ok on installing the driver unsigned.

USB Serial Adapter

The latest driver version is required to work with 10.9.

Plugable USB to RS-232 DB9 Serial Adapter

Serial devices will be automatically created (“ls /dev | grep serial”" to see them), however the network control panel in 10.9 now no longer shows serial devices as connected, even when they’re in use.

Other Devices

For all of our other devices, we’re recommending in-box drivers, or they don’t require 3rd party driver installs (hubs, cables, etc).

If you have a question about a product we didn’t mention, please feel free to comment below. We’ll get it added.

And if you hit any 10.9 upgrade problems with Plugable products, we’ll work to help. Just email support@plugable.com anytime.

Thanks!