Plugable adapter displays video intermittently


#1

My plugable connector sometimes works fine. Other times it flickers on and off intermittently. Seems completely random. Driver has been uninstalled/reinstalled. This happens on multiple displays.

System is Mac OS X 10.6.8 with a third display connected via a Thunderbolt port.


#2

Hi Jerry,

Thanks for posting! There are a few different potential sources for multi-monitor troubles on Mac. Let’s try to untangle what’s happening.

First off, could you say exactly what model of Mac you have? The main thing we need to figure out is whether it has hybrid/switching graphics (Intel/nVidia or Intel/ATI), as this is the most common cause of problems.

There are some fundamental issues with multiple displays on Lion, waiting on Apple fixes. But since you’re on 10.6.8 those shouldn’t apply.

And in terms of DisplayLink driver, are you already at the latest DisplayLink 1.7 beta 4 driver (available here: http://displaylink.org/forum/showthre…)

Thanks for letting us know - from this we’ll figure out next steps.

Thanks for your patience!
Bernie


#3

Hi Bernie,

It’s a MacBook Pro 2.2 GHz Intel Core i7 with 8GB of RAM. It has a Radeon HD 6750M card along with Intel HD Graphics 3000 built-in graphics.

Not running Lion on this computer.

Installed the 1.7 beta 4 driver yesterday (after uninstalling the previous driver) and the issue occurred again this morning. Seems like it only occurs when I first start working then after about 30minutes to an hour it normalizes.

After the most recent occurrence this morning I disabled automatic switching. While it didn’t immediately resolve the issue after keeping it disconnected for about 30 minutes then reconnecting it works fine.

Thanks!
Jerry


#4

Actually, it’s still happening fairly frequently this morning, just intermittently.


#5

Hi Jerry,

Thanks for this additional info! The switchable Intel/ATI graphics are probably playing a part, in combination with using a mix of internal, DisplayPort, and DisplayLink displays.

All the display technologies are making use of the main GPU (in different ways).

In a way, it’s good that it’s happening fairly frequently - we’ll be able to try things and know if it helps.

Two quick questions:

* When automatic switching was disabled, were you able to set it to use the higher power GPU (ATI)? That’s what we’d recommend if possible.

* If you temporarily disconnect the DisplayPort monitor to get that out of the picture, does it affect the flicker on the USB display at all?

Thanks for letting us know,
Bernie


#6

Hi Bernie,

Yes, disabling auto switching forces the computer to always use the GPU rather than on-board graphics.

Whether the display-port is connected or not makes no difference.

Any other advice you have is appreciated.

Jerry


#7

Hi Jerry,

Just to rule out a problem with the unit, do you happen to have a Windows machine around that you could try the adapter on? (blasphemy, I know, in some quarters … :wink: )

Bernie


#8

No problem, Bernie. I work in a Mac-PC integrated envirnoment…no blasphemy taken.

The unit only works occasionally now, and wouldn’t work at all when connected to a Windows computer with the DisplayLink driver installed. I’m suspecting a bad unit.

We have more of these on order so I’ll be able to test for sure. Assuming it’s a bad unit, what’s the next step?

Thanks,
Jerry


#9

No problem - just email support@plugable.com with the Amazon order number - we’ll replace a bad unit right away. Thanks for your patience!


#10