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).

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

This update is compatible with and applies to all Plugable USB graphics adapters and docks.

This is great news, as this new version includes a few important fixes and features, and many small ones. Details below.

Notes

• Windows 7 makes Windows Update for hardware automatic, but it can be enabled for Vista and XP also
• The update will automatically be triggered by Windows when it sees a new device. Or for an existing device, you can trigger Windows Update manually, and look for DisplayLink’s drivers among the “Optional” updates.

Important Features/Fixes from 5.5 to 5.6 M1

• Fix for software-triggered screen freezes (which required system reboot or service restart)
• Support for Windows Server SKUs (with Aero installed and enabled)
• Better compatibility with nVidia and ATI GPUs
• Improved compatibility with newer DirectX apps

Full changelist from DisplayLink

C1. Fixed issues between R5.6 (5.6.31721.0) and R5.6 M1 (5.6.31854.0)
—————————————

If the reboot prompt after install is ignored on Windows XP, then the
DisplayLink monitor set to mirror may display corrupted data. (10953)

After installing DisplayLink software on some systems with switchable graphics
architectures, the main monitor may be dimmed and not responsive until reboot.
(10534)

Monitor details were not being updated in “Devices and Printers” folder when
changing the monitors connected to DisplayLink device. (9917)

DisplayLink monitors may flash occasionally when playing fullscreen videos on
several stations. (11173)

On Windows XP after installing DisplayLink drivers several reboot cycles may be
requested. (11079)

C1. Fixed issues between R5.5 (5.5.27797) and R5.6 (5.6.31721.0)
—————————————
DisplayLink Software upgraded through Windows Update will not work correctly
after rebooting the system (issue affecting releases R5.3 to R5.4 on Windows
update). (9658)

Blue screen on Windows 7 on some platforms when rebooting after having applied
layout changes. (9631)

The DisplayLink GUI stops functioning correctly after switching GPU on some
ATI/Intel hybrid systems. (10065, 10106)

Sometimes there are two DisplayLink icons present in the system tray. (9807)

Sometimes the DisplayLink icon is missing in the system tray. (9545, 9837)

Video in Basic Mode not working with the latest Windows updates on both Windows
Vista and Windows 7. (1609)

Video playback issues on Microsoft Windows 7 with the latest NVIDIA Drivers.
(10061)

A DisplayLink USB monitor could occasionally remain blank after a PC reboot.
(9622)

DirectX 9 games could crash when running on a primary, non DisplayLink, screen.
(10027)

DisplayLink software fails to install on NVidia Quadro FX 880M graphics card.
(9637)

On Windows 7 Windows Photo Viewer may show corruption when a DisplayLink
monitor is mirroring the main screen. (9612)

On some systems with switchable graphics architectures disconnecting
a DisplayLink monitor may cause main monitor to be switched off. (9750, 9747)

Screen corruption while performing the Aero 3D flip (Windows+tab) interface
effect. (10425)

Blue screen when restarting with a connected DisplayLink screen in Projector
Only mode. (10457)

After a series of layout changes the DisplayLink screens can sometimes freeze
while the DisplayLink GUI loses functionality. (10489)

2 DisplayLink GUIs are shown in the system tray after installation. (10504)

Blue screen when using a DisplayLink device for the first time on some Optimus
configurations. (10700)

On some Optimus configurations, rebooting with a DisplayLink device connected
causes the DisplayLink screens to remain black with a blinking mouse pointer.
(10701, 10702)

Screen corruption when using 3D GUI effects on DisplayLink screens in some
display configurations. (9611, 10425)

Screen corruption on DisplayLink screens while using some applications after a
transition from projector mode to duplicate. (9612)

Video in Basic Mode not working with the latest Windows updates on both Windows
Vista and Windows 7. (1609)

In rare scenarios a DisplayLink monitor may freeze. (10230)

DisplayLink USB monitor could occasionally remain blank after a PC reboot.
(9622)

Blue screen when playing video on multiple clients. (6309, 9442)

SRC Shell application crashed when playing video clip. (10212)

When the logon screen is displayed, occasionally the DisplayLink displays are
frozen and only updated by the mouse pointer. (10044)

On some switchable systems the main screen flashes continuously after
installing the DisplayLink driver or after connecting the DisplayLink device.
(10653)

Corruption is shown while moving the cursor near the edge of a window on top of
a Windows Media Player window. (10752)

Incorrect/missing Windows Update error reporting from the DisplayLink GUI.
(10523)

Sometimes a Windows XP computer with DisplayLink drivers installed will hang
while starting. (9607)

On some nVidia Optimus systems the DisplayLink display will remain black
immediately after installing the DisplayLink drivers. A reboot recovers from
this issue. (10785)

On some machines Windows falls into endless reboot loop after installation of
DisplayLink drivers. (10918)

Timing not compliant with the CEA861D specification. (10952)

DisplayLink has released an updated Mac driver (1.7 beta 1) with support for Mac OX 10.7 “Lion” (both 32 and 64 bit kernels).

The driver is available for download now at http://displaylink.com/support/mac_downloads.php and is compatible with all Plugable USB graphics adapters and docking stations, such as the Plugable UGA-2K-A.

DisplayLink’s release coincided with Apple’s announcement today at WWDC that the Lion update will be available for purchase next month for $29. Driver updates from DisplayLink are free.

This new line of DisplayLink drivers (1.7 and later) is critical for all DisplayLink Mac users looking to upgrade to Lion, as the new OS release breaks all older USB graphics drivers.

The new DisplayLink driver release includes other fixes, but retains the same high-level characteristics and limitations of prior Mac driver versions (displays up to 2048×1152 on high-end USB adapters; limit of 4 additional displays via 4 USB adapters; no Quartz Extreme/OpenGL support).

We’re recommending that affected users download this latest DisplayLink 5.5 M1 (Dec 3, 2010) release or any later version, available at http://displaylink.com/support/downloads.php

Note a reboot may be required as the installer removes the prior version, and installs the new. Please feel free to comment with any experience reports or problems.

Here’s a rundown of important problems that are intended to be fixed from 5.5 (Sept 29, 2010) to 5.5 M1 (Dec 3, 2010) from the DisplayLink 5.5 M1 release notes. We have some notes from us [in brackets] based on what we’ve seen from Plugable customers.

These issues have complete or partial fixes in 5.5. M1:

• Video playback issues on Microsoft Windows 7 with the latest NVIDIA Drivers. [This is the big incompatibility where nVidia drivers after 258.96 broke DirectX functionality on systems with DisplayLink drivers installed]
• DisplayLink Software upgraded through Windows Update will not work correctly after rebooting the system (issue affecting releases R5.3 to R5.4 on Windows update). [This problem has kept the DisplayLink version on Microsoft's Windows Update system to the older version 5.2, meaning that users who simply plug in their device without a manual driver download have been missing fixes for a number of serious known issues. Now DisplayLink should be able to resume delivering the very latest drivers via Windows Update]
• DisplayLink USB monitor could occasionally remain blank after a PC reboot. [we've seen this problem intermittently from several customers. We suspect multiple causes, but hope this resolves most]
• Sometimes the DisplayLink icon is missing in the system tray. [this had previously been a sign of larger problems]

And other important problems DisplayLink reports fixed, that we haven’t specifically run across:

• Blue screen on Windows 7 on some platforms when rebooting after having applied layout changes.
• The DisplayLink GUI stops functioning correctly after switching GPU on some ATI/Intel hybrid systems.
• Sometimes there are two DisplayLink icons present in the system tray.
• Video in Basic Mode not working with the latest Windows updates on both Windows Vista and Windows 7.

5.5 M1 is compatible with all Plugable USB graphics devices. Generally DisplayLink does a good regression testing so we’ve generally had a good experience being aggressive about upgrading to get the latest fixes (when things break, they break more often between DisplayLink releases because of external OS or other main GPU driver changes). So we’re recommending this release to all Plugable users who are experiencing any of the problems above.

nVidia’s latest Win7/Vista drivers (October 18, 2010 and later) conflict with existing DisplayLink drivers (version 5.5 Sept 29th and earlier), causing video playback and some 3D applications to not function. These problems apply to all DisplayLink-based USB graphics products, including ours.

DisplayLink is working to fix the conflicts. They’re trying to roll out updated drivers as quickly as possible, but have some work to do yet.

On Nov 15 they made available a maintenance release of the older DisplayLink driver version 5.4, called “5.4 M1″, which resolves some of the conflict, but not enough to make the solution workable.

Our recommended solution for now is to use the latest DisplayLink drivers, and stay on or move back to nVidia drivers version 258 or earlier. For Windows 7 and Vista 32-bit, you can find the nVidia drivers here. For 64-bit, find them here. These drivers do not have any of these these 3D & video playback conflicts.

Our apologies to users affected by these conflicting drivers. We hope this information helps. Feel free to email support@plugable.com or visit http://plugable.com/support/ and post a question if you have any remaining problems. Again, thank you!

[updated 11/23]

The UD-160-A and other powered CM-6300 devices can be configured in hardware to deliver high power audio output, so it’s great even with unpowered speakers. But for headsets and self-powered speakers, the defaults may be too loud.

For those cases and others, here are some details and tips for adjusting the volume in Windows 7 with USB audio.

First off, it helps to bring up some music in Windows Media player so you can hear the affect of your settings changes. Most Windows 7 installs will have some sample music to play in Libraries->Music->Sample Music

Then, go to where the settings are collected — in the “Sound” settings from the Windows 7 Control Panel.

This will bring up the list of available audio devices, one of which should be your USB audio device. By default, Windows 7 makes a new USB audio device the default — even if it doesn’t have any speakers attached! So this is also the place where, if you’re not actually using your USB or docking station audio, you can select a different audio output (e.g. your laptop’s built-in audio) and click “Set Default” to make it the default for new default sound output and/or for communications (messenger/skype/voip). Windows will persist this setting.

For adjusting the USB audio level, right click on the USB audio device to bring up the context menu and select “Properties”.

The main volume for the device is in the “Levels” tab. When this audio device is the default device, this level is the same as the Windows master audio volume controls (the one you adjust from the sound icon in the Windows system tray) — adjusting one will adjust the other. The default in Windows is a max volume of “100″.

For the high-power audio of the Plugable dock, combined with powered speakers, “100″ is often too loud, and you may find that even setting the level to “1″ is still too loud.

The solution is the “Custom” tab which has an optional “Loudness” checkbox (provided by the Microsoft USB audio class drivers). Windows 7 sets this on by default, but in most cases it should be unchecked. Then, go back to your levels tab and re-adjust the volume to the right and comfortable level.

For most speaker combinations, you should no longer be having to peg the volume down at “1″.

And once you have master volume at a comfortable level – you also have another means of control. Each application has its own volume, which acts in combination with the Windows master settings. So if system sounds or media playback are still to loud or not the right relative volume, look within the particular application for its own sound slider (and most applications will persist this setting).

We hope this helps for anyone experiencing audio which is too loud or too quiet with any Plugable or other USB audio devices on Win 7. Please feel free to comment with any questions or other suggestions.

[Update March 2, 2011]

If you’re on Windows, and the above steps don’t help enough, there is a Windows driver solution to bump the volume down further.

This driver replaces Windows’ default USB audio driver, it’s compatible with the CM6300 in the Plugable Universal Dock. Most functionality doesn’t apply to the CM6300, but the fine grained control over volume is better and helpful.

Here’s where you can download the lower-volume CM6300 driver. Please let us know in the comments if you have any problems or feedback. Thanks!

This update is compatible with all of Plugable’s products with DisplayLink-based USB graphics.

This is a must-have update for all with machines with ATI/AMD as their primary graphics controller, as it works around serious issues introduced with ATI’s Catalyst™ 10.8 driver release. ATI’s driver was released just recently (August). ATI has not pushed this update widely, but over time we expect more ATI/AMD users will need to make sure they’re running DisplayLink driver version 5.5 or later.

In terms of new features, DisplayLink’s version 5.5 driver also includes:

• Windows Presentation Foundation compatibility on Windows XP — a big deal for XP users who use Visual Studio 2010 or any of the other (limited but growing) list of applications built on WPF
• ‘Fit to TV’ functionality for HDMI TVs
• GUI menu enhancements
• Some improvements in motion video playback performance on Windows 7 and Vista

See the 5.5 release notes for details.

The main feature of the new beta are fixes for some problems experienced on resume from sleep.

In terms of our general recommendations for Macs and Plugable’s DisplayLink-based products, we still want to emphasize that all Mac drivers are of a beta/pre-release level of quality compared to the Windows products. They still 1) are incompatible with recent MacBook Pros with switching graphics 2) disable the USB ethernet interface on docking stations like our Plugable dock. 3) are too frequently broken or fixed by Apple’s OS X updates — Apple often seems to be changing driver interfaces in subtle ways that affect USB graphics.

We expect and hope that support from both DisplayLink and Apple will improve in time, and we’ll be able to recommend the combination without qualification. Until then, it’s good to see releases like this for incremental progress.

Linux is a big and constantly shifting platform. With our USB graphics products (and generally for DisplayLink based products, since we try to make them work for all devices), it’s easy to output a few pixels, but configuring a USB display as an X terminal, or certainly for an extended desktop, is still a process on Linux that requires manual xorg.conf editing and is for very advanced users only. But we try to contribute what we can at Plugable, and that has meant focusing on making the kernel driver that actually talks to the hardware and everything else builds on, as solid as possible.

The contributed patches start with this post to the linux driver project list.

————–
To: devel-request@linuxdriverproject.org
[PATCH 0/11] staging: udlfb: patches from udlfb development branch (Bernie Thompson)

This patch series contains all current fixes and features from
the udlfb development branch.

udlfb is a framebuffer driver for DisplayLink USB 2.0 era chips.

Diffstat of this 11 part patch series:

udlfb.c | 989 +++++++++++++++++++++++++++++++++++++++++———————–
udlfb.h | 41 +-
2 files changed, 664 insertions(+), 366 deletions(-)

Major changes:

* Added summary documentation for users of udlfb
* Added logic to query DisplayLink chip for max area mode,
so low-end chips on high-end monitors no longer get black screen
* Added support for DPMS. X servers now control monitor
power with existing standard interface
* Added back in support for char interface (e.g. cat file > /dev/fb0)
* Systems without EDID or with failing EDID can now supply fixed
EDID to sysfs interface, also avoiding black screen
* Fixed big-endian (PowerPC) rendering
* Fixed teardown race conditions that could result in shutdown hang
* Added fb_defio and fb console module options (default off)
* Fixed udlfb’s fb_defio client code so no longer incorrectly shares
state across udlfb device instances – fixes hangs and errant rendering
* Removed IFDEFs for building against older kernels – those will
be retained in the udlfb development branches at git.plugable.com

Todo:

There have been no additional reported bugs in the last few months,
although there are several wishlist features. Udlfb may be ready
to move out of staging at this point.

Patches are against Linus’ latest 2.6 tree.

This complete quilt patch series can be downloaded from http://plugable.com/udlfb-patches-2.6.35-v2.tgz