Difference between revisions of "DisplayLink"

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[[Category:Other hardware]]
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[[Category:Displays]]
The following steps are the most recent ones that the DisplayLink support guy was suggesting. I packaged the revisions in AUR, that compiled and worked great so far.
+
[[ja:DisplayLink]]
According to the Plugable information they should work with almost every DisplayLink (DL-1**) device although they don't suggest using their devices with Linux for production use for now.
+
DisplayLink devices on Linux still only have experimental support. While some people have had success in using them, it is generally not an easy process and not guaranteed to work. The steps on this page describe the generally most successful methods of using external monitors with DisplayLink.
 +
 
 +
Also be warned that even over USB 3.0, a DisplayLink monitor may exhibit noticeably more lag than e.g. a DisplayPort monitor, especially when large portions of the screen are being redrawn.
  
 
==Installation==
 
==Installation==
  
Install the packages `udlfb` and `xf86-video-fbdev-for-displaylink`. Remember to remove any of them if already installed. The `xf86-video-fbdev-for-displaylink` is originally a patched `xf86-video-fbdev`, so you need to remove that one. Also keep the order when installing.
+
=== USB 2.0 DL-1xx Devices ===
  
* [https://aur.archlinux.org/packages.php?ID=53654 UDLFB]
+
The kernel [[Wikipedia: Direct_Rendering_Manager|DRM]] driver for DisplayLink is {{ic|udl}}, a rewrite of the original [https://www.kernel.org/doc/Documentation/fb/udlfb.txt udlfb] driver. It allows configuring DisplayLink monitors using [[Xrandr]].
* [https://aur.archlinux.org/packages.php?ID=53656 xf86-video-fbdev]
+
 
 +
First, the setup and installation:
 +
 
 +
* [[Blacklist]] the old kernel module, {{ic|udlfb}}, which may attempt to load itself first.
 +
 
 +
=== USB 3.0 DL-5xxx, DL-41xx, DL-3x00 Devices ===
 +
 
 +
# Install the {{AUR|displaylink}} driver. It allows configuring DisplayLink monitors using [[Xrandr]] in the same manner as the {{ic|udl}} driver.
 +
# Enable {{ic|displaylink.service}}.
 +
 
 +
=== Setting up X Displays ===
 +
 
 +
After that, run:
 +
 
 +
{{hc|$ xrandr --listproviders|<nowiki>
 +
Providers: number : 2
 +
Provider 0: id: 0x49 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 2 outputs: 8 associated providers: 0 name:Intel
 +
Provider 1: id: 0x13c cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting
 +
</nowiki>}}
 +
 
 +
In the above output, we can see that provider 0 is the system's regular graphics provider (Intel), and provider 1 (modesetting) is the DisplayLink provider. To use the DisplayLink device, connect provider 1 to provider 0:
 +
 
 +
$ xrandr --setprovideroutputsource 1 0
 +
 
 +
and xrandr will add a DVI output you can [[Xrandr#Configuration|use as normal with xrandr]]. This is still experimental but supports hotplugging and when works, it is by far the simplest setup. If it works then everything below is unnecessary.
  
 
==Configuration==
 
==Configuration==
  
These instructions assume that you already have an up and running X server and are simply adding a monitor to your existing setup.  You should also have a knowledge of installing from the [[AUR]] and an active internet connection.
+
These instructions assume that you already have an up and running X server and are simply adding a monitor to your existing setup.
  
 
===Load the framebuffer device===
 
===Load the framebuffer device===
You installed the udlfb kernel module, but it has to be loaded in order for the kernel to see the DisplayLink device. When loading make sure that you activate the `fb_defio` flag.
 
  
  # modprobe udlfb fb_defio=1
+
Before your system will recognize your DisplayLink device, the {{ic|udl}} kernel module must be loaded. To do this, run
 +
 
 +
  # modprobe udl
 +
 
 +
If your DisplayLink device is connected, it should show some visual indication of this. Although a green screen is the standard indicator of this, other variations have been spotted and are perfectly normal. Most importantly, the output of {{ic|dmesg}} should show something like the following, indicating a new DisplayLink device was found:
 +
 
 +
{{bc|<nowiki>usb 2-1.1: new high-speed USB device number 7 using ehci-pci
 +
usb 2-1.1: New USB device found, idVendor=17e9, idProduct=03e0
 +
usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
 +
usb 2-1.1: Product: Lenovo LT1421 wide
 +
usb 2-1.1: Manufacturer: DisplayLink
 +
usb 2-1.1: SerialNumber: 6V9BBRM1
 +
[drm] vendor descriptor length:17 data:17 5f 01 00 15 05 00 01 03 00 04
 +
udl 2-1.1:1.0: fb1: udldrmfb frame buffer device
 +
[drm] Initialized udl 0.0.1 20120220 on minor 1
 +
</nowiki>}}
 +
 
 +
Furthermore, {{ic|/dev}} should contain a new {{ic|fb}} device, likely {{ic|/dev/fb1}} if you already had a framebuffer for your primary display.
 +
 
 +
To automatically load {{ic|udl}} at boot, create the file {{ic|udl.conf}} in {{ic|/etc/modules-load.d/}} with the following contents:
 +
 
 +
{{hc|/etc/modules-load.d/udl.conf|udl}}
 +
 
 +
For more information on loading kernel modules, see [[Kernel modules#Automatic module handling]].
 +
 
 +
===Configuring X Server===
 +
Use {{ic|xrandr}} or your Desktop Environment's display setup UI to configure your USB monitors running either the {{ic|udl}} or {{ic|displaylink}} driver.
 +
 
 +
====xrandr====
 +
 
 +
Once the driver is loaded, the DisplayLink monitor is listed as an output provider:
 +
 
 +
{{hc|$ xrandr --listproviders|<nowiki>
 +
Providers: number : 2
 +
Provider 0: id: 0x43 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 2 outputs: 2 associated providers: 1 name:Intel
 +
Provider 1: id: 0xcb cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
 +
</nowiki>}}
 +
In the above example, provider 1 is the DisplayLink device, and provider 0 is the default display. Running {{ic|xrandr --current}} gives a list of available screens:
 +
 
 +
{{hc|$ xrandr --current|<nowiki>
 +
Screen 0: minimum 320 x 200, current 1600 x 900, maximum 8192 x 8192
 +
LVDS1 connected 1600x900+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
 +
  1600x900      60.0*+  40.0 
 +
  1440x900      59.9 
 +
  1360x768      59.8    60.0 
 +
  1152x864      60.0 
 +
  1024x768      60.0 
 +
  800x600        60.3    56.2 
 +
  640x480        59.9 
 +
VGA1 disconnected (normal left inverted right x axis y axis)
 +
DVI-1-0 connected (normal left inverted right x axis y axis)
 +
  1366x768      60.0 +
 +
  1368x768_59.90  59.9 
 +
  1368x768_59.90 (0xd0)  85.7MHz
 +
        h: width  1368 start 1440 end 1584 total 1800 skew    0 clock  47.6KHz
 +
        v: height  768 start  769 end  772 total  795          clock  59.9Hz
 +
</nowiki>}}
 +
 
 +
If the above does not list the DisplayLink screen, then you will need to offload DisplayLink to the main GPU:
 +
 
 +
{{bc|xrandr --setprovideroutputsource 1 0}}
 +
 
 +
Once the screen is available, refer to [[Xrandr]] for info on setting it up. For automating the configuration process, see [https://github.com/nathantypanski/displaylink.sh displaylink.sh].
 +
 
 +
====Enabling DVI output on startup====
 +
The DisplayLink provider will not be automatically connected to the main provider in most cases, therefore the DVI output device will not be available. It can be helpful to automatically do this when X starts to facilitate automatic display configuration by the window manager.
 +
 
 +
Edit your desktop manager's startup configuration and add commands similar to:
 +
{{bc|<nowiki>
 +
$(xrandr --listproviders | grep -q "modesetting") && xrandr --setprovideroutputsource 1 0
 +
</nowiki>}}
 +
 
 +
For example, the appropriate startup configuration file for [[SDDM]] is {{ic|/usr/share/sddm/scripts/Xsetup}}.
 +
 
 +
Avoid placing these commands in {{ic|~/.xprofile}} as this breaks the display configuration of some window managers. Instead these commands should be run prior to any display output or setup.
  
At this point, if your monitor is connected, it should go from either a black screen or the red-green-blue-checkers test pattern to a solid green screen, indicating the framebuffer is loaded and ready for an application to use it. You should also see a new device in /dev, likely '''/dev/fb1'''.
+
{{Note|If you have additional providers, specify the name of the provider instead of using indexes. The name of the DisplayLink device will be {{ic|modesetting}}}}
  
To automatically load it at boot, udlfb and it´s parameters need to be built into mkinitcpio. Therefore create or change the following conf files:
+
== Troubleshooting ==
  
{{hc|/etc/modprobe.d/udlfb.conf|2=options udlfb fb_defio=1}}
+
=== Not working configuration ===
  
{{hc|/etc/mkinitcpio.conf|2=MODULES="... '''udlfb''' ..."
+
These are tested on [[Xfce]] using Display settings (included in XFCE4 package) and external tool - {{pkg|arandr}}. XFCE4 Display settings are likelly to crash, so ARandR might help.
FILES="'''/etc/modprobe.d/udlfb.conf'''"}}
+
  
Then, rebuild the kernel image:
+
When you connect display link device via USB to your computer, the computer should show monitors in Display settings. There are few troubleshooting steps that you should try:
  
# mkinitcpio -p linux
+
* Check [[#Setting up X Displays]]. If you can find any external monitors recognized, you should try to make them visible by the following commands:
 +
{{bc|<nowiki>xrandr --setprovideroutputsource 1 0
 +
xrandr --setprovideroutputsource 2 0
 +
xrandr --setprovideroutputsource 3 0
 +
...
 +
</nowiki>}}
 +
This will make them visible and recognized in Display settings.
 +
* Restart {{ic|displaylink.service}}.
 +
* Re-connecte USB cable.
 +
* Check if {{ic|udl}} driver is loaded and monitors are connected.
  
For more information on this, see [[Mkinitcpio]].
+
=== Screen redraw is broken ===
 +
If you are using {{ic|udl}} as your kernel driver and the monitor appears to work, but is only updating where you move the mouse or when windows change in certain places, then you probably have the wrong modeline for your screen. Getting a proper modeline for your screen with a command like
  
===Update Xorg.conf===
+
{{bc|
You must update your xorg.conf in order to use your additional display.  When using the 710-S I was only able to use it if I set the DisplayLink device as screen0 and my internal display as screen1.  I do not know if this is a common problem or just local to my setup.
+
gtf 1366 768 59.9
 +
}}
  
Add this to the bottom of xorg.conf:
+
where {{ic|1366}} and {{ic|768}} are the horizontal and vertical resolutions for your monitor, and {{ic|59.9}} is the refresh rate from its specs. To use this, create a new mode with {{ic|xrandr}} like follows:
################ DisplayLink Stuff ###################
+
Section "Device"
+
        Identifier      "DisplayLinkDevice"
+
        Driver          "fbdev"
+
        BusID          "USB"              # needed to use multiple DisplayLink devices
+
        Option          "fbdev" "/dev/fb0"  # change to whatever device you want to use
+
#      Option          "rotate" "CCW"      # uncomment for rotation
+
EndSection
+
+
Section "Monitor"
+
        Identifier      "DisplayLinkMonitor"
+
EndSection
+
+
Section "Screen"
+
        Identifier      "DisplayLinkScreen"
+
        Device          "DisplayLinkDevice"
+
        Monitor        "DisplayLinkMonitor"
+
        DefaultDepth    16
+
EndSection
+
  
Then you can adjust your server layout to your needs. Well, almost.
+
{{bc|
 +
xrandr --newmode "1368x768_59.90"  85.72  1368 1440 1584 1800  768 769 772 795  -HSync +Vsync
 +
}}
  
Then edit your server layout to look something like this
+
and add it to [[Xrandr]]:
Screen 0 "DisplayLinkScreen"
+
Screen 1 "Internal" RightOf "DisplayLinkScreen"
+
Option "Xinerama" "on"
+
  
Change ''Internal'' to whatever your main display is called. Reboot your system and the two should be linked together!
+
{{bc|
 +
xrandr --addmode DVI-0 1368x768_59.90
 +
}}
  
==Troubleshooting==
+
Then tell the monitor to use that mode for the DisplayLink monitor, and this should fix the redraw issues. Check the [[Xrandr]] page for information on using a different mode.
  
===X crashes or keeps blank===
+
If this does not solve the problem (or if the correct modeline was already in place because of correct DDC data), it can help to run a compositor. E.g. when using plain i3, running {{Pkg|xcompmgr}} or {{Pkg|compton}} can mitigate the problem.
If X crashes, or nothing shows up when you boot, try to start X only using the external display
+
Screen 0 "DisplayLinkScreen"
+
#Screen 1 "Internal" RightOf "DisplayLinkScreen"
+
#Option "Xinerama" "on"
+
  
You may need to set your screen depths to be the same. Make sure that in both ''Screen'' sections it is set to 16.
+
=== DisplayLink refresh rate is extremely slow with gnome 3 ===
(This is because xinerama require that the screens use the same bitdepth)
+
If once you set up your DisplayLink your entire desktop becomes slow, try setting a "simpler" background image, such as complete black.
DefaultDepth 16
+
  
'''With fbdev this is not true anymore, because fbdev provides virtual 24bit support. Just use everything with DefaultDepth 24.'''
+
==See Also==
  
===Cannot start in framebuffer mode. Please specify busIDs for all framebuffer devices===
+
* [http://displaylink.org/forum/forumdisplay.php?f=29 DisplayLink Open Source]: Official DisplayLink open source support forum
I have not yet been able to correct this issue. It seems like it's an incompatibility between fbdev and nvidia driver.
+
* [http://plugable.com/platforms/linux Plugable]: Vendor blog chronicling Linux support for DisplayLink.
 +
* [http://www.displaylink.com/downloads/ubuntu.php Ubuntu Driver Download]: DisplayLink Ubuntu Driver Download and Information
 +
* [http://downloads.displaylink.com/releasenotes/DisplayLink_Ubuntu_1.0.68_release-note.txt Release Notes]: Latest release notes for DisplayLink Ubuntu Software

Latest revision as of 08:30, 6 July 2016

DisplayLink devices on Linux still only have experimental support. While some people have had success in using them, it is generally not an easy process and not guaranteed to work. The steps on this page describe the generally most successful methods of using external monitors with DisplayLink.

Also be warned that even over USB 3.0, a DisplayLink monitor may exhibit noticeably more lag than e.g. a DisplayPort monitor, especially when large portions of the screen are being redrawn.

Installation

USB 2.0 DL-1xx Devices

The kernel DRM driver for DisplayLink is udl, a rewrite of the original udlfb driver. It allows configuring DisplayLink monitors using Xrandr.

First, the setup and installation:

  • Blacklist the old kernel module, udlfb, which may attempt to load itself first.

USB 3.0 DL-5xxx, DL-41xx, DL-3x00 Devices

  1. Install the displaylinkAUR driver. It allows configuring DisplayLink monitors using Xrandr in the same manner as the udl driver.
  2. Enable displaylink.service.

Setting up X Displays

After that, run:

$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x49 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 2 outputs: 8 associated providers: 0 name:Intel
Provider 1: id: 0x13c cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

In the above output, we can see that provider 0 is the system's regular graphics provider (Intel), and provider 1 (modesetting) is the DisplayLink provider. To use the DisplayLink device, connect provider 1 to provider 0:

$ xrandr --setprovideroutputsource 1 0

and xrandr will add a DVI output you can use as normal with xrandr. This is still experimental but supports hotplugging and when works, it is by far the simplest setup. If it works then everything below is unnecessary.

Configuration

These instructions assume that you already have an up and running X server and are simply adding a monitor to your existing setup.

Load the framebuffer device

Before your system will recognize your DisplayLink device, the udl kernel module must be loaded. To do this, run

# modprobe udl

If your DisplayLink device is connected, it should show some visual indication of this. Although a green screen is the standard indicator of this, other variations have been spotted and are perfectly normal. Most importantly, the output of dmesg should show something like the following, indicating a new DisplayLink device was found:

usb 2-1.1: new high-speed USB device number 7 using ehci-pci
usb 2-1.1: New USB device found, idVendor=17e9, idProduct=03e0
usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-1.1: Product: Lenovo LT1421 wide
usb 2-1.1: Manufacturer: DisplayLink
usb 2-1.1: SerialNumber: 6V9BBRM1
[drm] vendor descriptor length:17 data:17 5f 01 00 15 05 00 01 03 00 04
udl 2-1.1:1.0: fb1: udldrmfb frame buffer device
[drm] Initialized udl 0.0.1 20120220 on minor 1

Furthermore, /dev should contain a new fb device, likely /dev/fb1 if you already had a framebuffer for your primary display.

To automatically load udl at boot, create the file udl.conf in /etc/modules-load.d/ with the following contents:

/etc/modules-load.d/udl.conf
udl

For more information on loading kernel modules, see Kernel modules#Automatic module handling.

Configuring X Server

Use xrandr or your Desktop Environment's display setup UI to configure your USB monitors running either the udl or displaylink driver.

xrandr

Once the driver is loaded, the DisplayLink monitor is listed as an output provider:

$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x43 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 2 outputs: 2 associated providers: 1 name:Intel
Provider 1: id: 0xcb cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting

In the above example, provider 1 is the DisplayLink device, and provider 0 is the default display. Running xrandr --current gives a list of available screens:

$ xrandr --current
Screen 0: minimum 320 x 200, current 1600 x 900, maximum 8192 x 8192
LVDS1 connected 1600x900+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
   1600x900       60.0*+   40.0  
   1440x900       59.9  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 disconnected (normal left inverted right x axis y axis)
DVI-1-0 connected (normal left inverted right x axis y axis)
   1366x768       60.0 +
   1368x768_59.90   59.9  
  1368x768_59.90 (0xd0)   85.7MHz
        h: width  1368 start 1440 end 1584 total 1800 skew    0 clock   47.6KHz
        v: height  768 start  769 end  772 total  795           clock   59.9Hz

If the above does not list the DisplayLink screen, then you will need to offload DisplayLink to the main GPU:

xrandr --setprovideroutputsource 1 0

Once the screen is available, refer to Xrandr for info on setting it up. For automating the configuration process, see displaylink.sh.

Enabling DVI output on startup

The DisplayLink provider will not be automatically connected to the main provider in most cases, therefore the DVI output device will not be available. It can be helpful to automatically do this when X starts to facilitate automatic display configuration by the window manager.

Edit your desktop manager's startup configuration and add commands similar to:

$(xrandr --listproviders | grep -q "modesetting") && xrandr --setprovideroutputsource 1 0

For example, the appropriate startup configuration file for SDDM is /usr/share/sddm/scripts/Xsetup.

Avoid placing these commands in ~/.xprofile as this breaks the display configuration of some window managers. Instead these commands should be run prior to any display output or setup.

Note: If you have additional providers, specify the name of the provider instead of using indexes. The name of the DisplayLink device will be modesetting

Troubleshooting

Not working configuration

These are tested on Xfce using Display settings (included in XFCE4 package) and external tool - arandr. XFCE4 Display settings are likelly to crash, so ARandR might help.

When you connect display link device via USB to your computer, the computer should show monitors in Display settings. There are few troubleshooting steps that you should try:

  • Check #Setting up X Displays. If you can find any external monitors recognized, you should try to make them visible by the following commands:
xrandr --setprovideroutputsource 1 0
xrandr --setprovideroutputsource 2 0
xrandr --setprovideroutputsource 3 0
...

This will make them visible and recognized in Display settings.

  • Restart displaylink.service.
  • Re-connecte USB cable.
  • Check if udl driver is loaded and monitors are connected.

Screen redraw is broken

If you are using udl as your kernel driver and the monitor appears to work, but is only updating where you move the mouse or when windows change in certain places, then you probably have the wrong modeline for your screen. Getting a proper modeline for your screen with a command like

gtf 1366 768 59.9

where 1366 and 768 are the horizontal and vertical resolutions for your monitor, and 59.9 is the refresh rate from its specs. To use this, create a new mode with xrandr like follows:

xrandr --newmode "1368x768_59.90"  85.72  1368 1440 1584 1800  768 769 772 795  -HSync +Vsync

and add it to Xrandr:

xrandr --addmode DVI-0 1368x768_59.90

Then tell the monitor to use that mode for the DisplayLink monitor, and this should fix the redraw issues. Check the Xrandr page for information on using a different mode.

If this does not solve the problem (or if the correct modeline was already in place because of correct DDC data), it can help to run a compositor. E.g. when using plain i3, running xcompmgr or compton can mitigate the problem.

DisplayLink refresh rate is extremely slow with gnome 3

If once you set up your DisplayLink your entire desktop becomes slow, try setting a "simpler" background image, such as complete black.

See Also