Platform | Plugable

Howto: DisplayLink USB Single Monitor on Linux

Posted on 23. Dec, 2011 by jerome in Using

Unfortunately, Linux doesn’t support multiple graphics adapters the way Windows does, which means you can’t just plug in USB graphics adapters and expect them to extend your desktop (the good news is there is progress on this support).

What is possible, however, is running a single DisplayLink adapter, or several with a Xinerama or multiseat configuration — just as long as you don’t expect to use your main GPU at the same time.

The single-display case is relatively easy to set up, and we’ll cover that here.

First, make sure you’re running kernel version 2.6.35 or later (Ubuntu 10.10 or later). For older kernel versions, you’ll need to update udlfb and run a modified fbdev X server (not covered in this post). On these kernel versions, when you plug in your DisplayLink-based USB graphics device, you should get a green screen. This means that at the driver built into the Linux kernel is happy, healthy, and talking to the device.

Second, if you are running Unity Desktop in Ubuntu 11.04 or later, you’ll need to switch back to Classic Mode so you’re running straight X. Here’s how on Ubuntu:

Click on the power button in the upper right corner (mine looks like a light switch) and choose the last option, System Settings. Search for Login Screen, Double-click to display, Choose Unlock and enter your password, Select Ubuntu Classic as default session.

Third, if you’re running kernel versions between 2.6.35 to 3.1, enable the fb_defio option of udlfb. To do this, create or edit a file like
/etc/modprobe.d/50-displaylink.conf

and add the single line

options udlfb fb_defio=1

And reboot (or run “sudo depmod -a” and unplug/replug your adapter). This will turn on defio (page fault change detection) support. This option is already enabled by default in kernels 3.2+.

Lastly, create an X config file called 60-plugable.conf (or similar) with the following contents and place it in /usr/share/X11/xorg.conf.d (on recent distros; on older distros, make this your xorg.conf):

 
Section "Device" 
  Identifier "uga" 
  driver "fbdev" 
  Option "fbdev" "/dev/fb0" 
EndSection 
 
Section "Monitor" 
  Identifier "monitor" 
EndSection 
 
Section "Screen" 
  Identifier "screen" 
  Device "uga" 
  Monitor "monitor" 
EndSection 
 
Section "ServerLayout" 
  Identifier "default" 
  Screen 0 "screen" 0 0 
EndSection

Note: if your main GPU creates a /dev/fb0 even when the USB display is not attached, then your USB display is probably getting assigned to /dev/fb1. In that case, change /dev/fb0 in the “Device” section above to /dev/fb1

Now, on reboot, you should (hopefully!) see your login come up on your DisplayLink USB attached display!

This kind of simple setup is useful for:

Testing or playing with your USB graphics adatper on Linux.
Embedded systems with USB but no GPU.
As a backup method when the main GPU or its driver isn’t available or working.
Systems where a USB graphics adapter enables higher modes (up to 2048×1152) than the main GPU screen.

Please comment if you have any trouble with this single display case. See our past posts for additional information about the DisplayLink Linux kernel driver and some more involved setups.

The instructed here work on all Plugable USB 2.0 graphics adapters and Plugable USB 2.0 docking stations and thin clients (and should also generally work on all DisplayLink based products).

DisplayLink’s Latest Windows Drivers (6.1 M0)

Posted on 17. Dec, 2011 by Bernie Thompson in Windows

DisplayLink has had two major updates to their Windows driver package this fall: 6.0 M1 and the newly released 6.1 M0.

For Plugable’s USB 2.0 products with DisplayLink chips, however, we’re still recommending earlier DisplayLink Windows driver version 5.6 M1 (5.6.31870.0), because of its proven stability. For now, Windows Update will still deliver 5.6 M1 automatically when you plug a Plugable device in.

Here’s a little background on why:

DisplayLink’s newest 6.x drivers work with all DisplayLink chips (USB 2.0 and the coming USB 3.0 generation), but the primary development focus of version 6.x has been on enabling the coming USB 3.0 generation of products. Perhaps as a result, there are some minor tradeoffs for USB 2.0 generation devices.

Here are the tradeoffs we’re following:

1) On a few systems, screens may go blank after returning from a reboot or power event. The cause appears to be changes in the way display configuration information is stored with the 6.0 and 6.1 drivers – Windows and the drivers can get confused, and that confusion will persist across unplugs, reboots, etc (going back to 5.6 M1 is the solution in these cases)
2) The uninstaller on version 6.1 fails to uninstall from Windows’ Programs and Features (as a workaround, you can use the DisplayLink “cleaner” utility).
3) 5.6 M1 is the last release where DisplayLink’s logs are readable. When we hit any strange problems on a customer’s system, our ability to analyze the logs to find the underlying problems (and solutions) is one of the ways we try to provide better support for Plugable brand devices.

All that said, we run the latest drivers on nearly all of our own systems (so we can stay up to date with the latest developments), and generally they’re great. So if there are any 6.x features or fixes that are relevant to you, feel free to download and install 6.1 M0 or later to give it a try. You can always download the latest DisplayLink driver here. And we expect that with one of the coming releases, we’ll push forward our recommendation to the latest version.

For those considering the latest versions, here’s the features and fixes DisplayLink has delivered since 5.6 M1 (as of version 6.1 M0). We’ve cut down the list to just those appear to be relevant to USB 2.0 devices.

New features since 5.6 M1 (as of 6.1 M0):

- Improved video smoothness for DL-1×0, DL-1×5 and DL-3×00 series
- Improved frame rate
- Reduced CPU utilization
- DisplayLink Tray applet enhancements

(Note these are generally subtle improvements)

New fixes since 5.6 M1 (as of 6.1 M0):

Sometimes the DisplayLink screen will remain blank when the device is
re-plugged after having been disconnected during power save. (11708)

Moving a mouse over full-screen video playback causes quality to drop. (12409)

Sometimes DisplayLink screen comes on in clone mode instead of extending when
connecting the device for the very first time. (10217)

Sometimes video may freeze on DisplayLink monitor. (11333)

Other miscellaneous fixes

The Celluon Magic Cube Laser Projection Keyboard Is Amazing

Posted on 04. Oct, 2011 by Bernie Thompson in Windows

There are a bunch of exciting things about the new Celluon Magic Cube Laser Keyboard:

It’s shocking to see a keyboard projected onto any table, and be able to type in thin air (that was also true of its predecessor, the Celluon LaserKey CL850)
You can connect to any PC or mobile with either with USB or Bluetooth. It uses a battery in wireless mode. That battery charges via its included USB cable
It now has a mouse mode with multi-touch support for Windows 7 (Doesn’t support Mac or iOS multitouch)

But the really important thing about the new Magic Cube is it’s now driverless: It uses the standard Bluetooth HID profile and standard USB HID class, so for whatever you connect it to, it just sees a standard USB keyboard or mouse (which have always used HID). No drivers, no fuss.

That makes the new Magic Cube work with nearly all devices out there that can use a standard Bluetooth or USB keyboard: iPad, iPod, iPhone, Windows, Mac, Linux, and lots of other mobiles and devices.

iOS devices, in particular, are well-matched because the built-in auto-correct is a great help for improving accuracy (which is the main remaining downside of a projection keyboard — it takes getting used to).

If you’ve never had the chance to try a laser keyboard, take a look at this video to see it in action.