Multihead (3 Montiors) Sabrent USB->HDMI problems

Aaron Plattner aplattner at
Mon Oct 6 18:13:31 PDT 2014

On 10/06/2014 04:44 PM, daidoji70 wrote:
> Hello xorg,
>     I wasn't who to mail so I thought I'd mail this mailing list and
> hopefully I can be pointed in the right direction.  At work I have been
> given 2 monitors to go along with my EliteBook 8540w (laptop).  I have
> gotten one of the external monitors to work with the DisplayLink
> connection but learned last week that as my laptop's graphic card
> "01:00.0 VGA compatible controller: NVIDIA Corporation GT216GLM [Quadro
> FX 880M] (rev a2)" only has two CRTC's I'd be restricted to only 2
> monitors (which seems a waste as I have 3).
> So I bought a Sabrent USB-HRHD USB->HDMI adapter.  Today with the help
> of a very nice person on #xorg for a moment via unplugging/plugging and
> unloading udlfb and forcing udl to load, got the monitor to show up,
> could move windows to the display but my mouse would not move there (it
> would just like stop on the middle monitor).
> However, while trying to troubleshoot that issue, I rebooted the machine
> and since then I have not been able to pick that provider up again
> (although the udl module seems to load just fine).
> Logs and information that seems to be relevant when talking to people on
> xorg below.  Please let me know if you need any other information or can
> point me in the right direction.
> Thanks in advance.

Are you plugging in the USB device before, or after starting the X 
server?  I haven't debugged why it happens, but I've had trouble getting 
the X server to recognize the device unless it's hotplugged while the 
server is already running.


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