Does the kernel REALLY have displaylink support?
 

Hi

I have a Lenovo LT1421 USB external monitor, which ubuntu recognises, so in lsusb I have:

Bus 003 Device 015: ID 17e9:03e0 DisplayLink

and in dmesg:

[ 2462.124838] usb 3-4: new high-speed USB device number 15 using xhci_hcd
[ 2462.144951] usb 3-4: New USB device found, idVendor=17e9, idProduct=03e0
[ 2462.144960] usb 3-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2462.144965] usb 3-4: Product: Lenovo LT1421 wide
[ 2462.144968] usb 3-4: Manufacturer: DisplayLink
[ 2462.144971] usb 3-4: SerialNumber: 6V9CAAB7
[ 2462.146656] [drm] vendor descriptor length:17 data:17 5f 01 00 15 05 00 01 03 00 04
[ 2462.226249] udl 3-4:1.0: fb1: udldrmfb frame buffer device
[ 2462.226258] [drm] Initialized udl 0.0.1 20120220 on minor 1

I do not see the display in xrandr (or in the displays panel). I have edited blacklist-framebuffer.conf to contain these two lines at the end:

# blacklist udl
blacklist udlfb

I have tried following the instructions on displaylink.org but there are lots of broken links and lots of software with missing dependencies and the like, and very little actual success stories. I have read the posts in this forum and others, but none of the solutions seem to be aimed at recent kernels (mine is 3.11 which is supposed to have DisplayLink drivers built in).

Has anyone got this working in ubuntu 13.x, and if so, can you help me please?

Thanks

Shaun

plugable UGA-2K-A with "mainstream" 3.11.10 kernel
 

I did a lot of reading this morning, and finally got a Plugable UGA-2K-A to work on Ubuntu 12.04.4 (precise) by installing and rebooting the mainstream 3.11.10 kernel:

I am also using the Saucy LTS Enablement Stack for 12.04 Precise

See also:

• Mainline 3.11.10 kernel for saucy
• How to make Ubuntu 13.04 Work With DisplayLink Monitor
• Using AOC USB monitor in Ubuntu 13.04 with DisplayLink

The key to this seems to be which kernel you're using--there are regressions in some of the Ubuntu kernels.

Ok. As soon as you see "udl 3-4:1.0: fb1: udldrmfb frame buffer device" you know that the kernel driver has bound. So far so good.

I cannot give you an explanation specific to ubuntu, but generically you need:

1. X with support for xrandr1.4
2. kernel 3.6 or newer
3. the "modesetting" X driver

As the kernel driver has bound you need the generic driver for framebuffers with kernel modesetting. That is the "modesetting" driver. Generally, if you've installed it, it will be loaded when you start X.

In addition you need to slave the second graphics device to the first. Before you do that xrandr will <b>not</b> show the attached monitors. Hence your trouble with xrandr.

For example:
xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x5a cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 5 associated providers: 0 name:radeon
Provider 1: id: 0x4ae cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

That lists the devices. In my case I need to slave provider 1 to provider 0:
xrandr --setprovideroutputsource 1 0

After that xrandr will list the display and you use it like a second monitor on a primary graphics device.

Any tips on getting consistent results from
?

It seems when I tell xrandr to go back to just the built-in LVDS on my laptop and unplug to take it home at the end of the day, the next day back at the office, when it wakes up, and I reattach the DisplayLink USB cable, xrandr cannot "re-find" the provider. I must restart XWindows for it to locate it and use again.

Thanks for this post, This helps alot. :)

setproviders fails
 

This all works for me until i get to the -setprovideroutputsource section

root@rome:~# xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x6e cap: 0x0 crtcs: 3 outputs: 2 associated providers: 0 name:modesetting
Provider 1: id: 0x205 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

root@rome:~# xrandr --setprovideroutputsource 1 0
X Error of failed request: BadValue (integer parameter out of range for operation)
Major opcode of failed request: 140 (RANDR)
Minor opcode of failed request: 35 ()
Value in failed request: 0x6e
Serial number of failed request: 16
Current serial number in output stream: 17

i have a dell inspiron 7737 which does does ndivia optimus, is that preventing the setprovideroutputsource ?

i have both a usb3.0 and usb2 displaylink device and the latest drivers from display link (evdi) and udl , udlfb doesn't work either.