Sun just got me a 2009-vintage MacBook, and I also asked for a DVI adapter; when it arrived it was a Mini DisplayPort to Dual-Link DVI Adapter, which is what you need for a 30-inch display (drool). It has lots of negative reviews and indeed I had problems with it, so I should publish the solution for others to find.

The Dual-Link has both a Mini DisplayPort plug and a USB plug. It took me a while to figure out that apparently the USB is just there to provide power for the thing.

So I plugged both of them into the MacBook, and it only sort of worked, and only sometimes. It was slow at recognizing the external 1920×1200 external screen and sometimes failed entirely.

When I put the Mac to sleep in laptop mode and woke it up plugged into the big screen with the top down, it never once managed to come up right. Which kind of makes sense, when you think about it; the adapter doesn’t see power till the Mac wakes up, so the Mac doesn’t see the display until a little bit after that.

I also noticed that I was getting complaints about power usage when I plugged things into the Mac’s other USB socket. So it occurred to me that maybe the MacBook just doesn’t have enough power available through the USB to make everything happy.

Fortunately, at the office, I have a powered USB hub, a cute little thing that can supply an amp or two on demand. If you don’t have one of these things in your office environment, I recommend one. With my witches’ brew of external DACs and other USB bits-and-bobs, it’s essential.

Anyhow, I plug the Adapter’s USB cable into the hub, and that leaves the Mini DisplayPort plug free to slip into the Mac. This does not wake it up from sleep, as it shouldn’t. Then when you plug the USB hub into your Mac, it wakes up and sees the external screen and all is well.

I went to a big-box store, thinking I was going to get another hub, but I found a basic (not Dual-link) Mini DisplayPort adapter on sale because the package had been opened, so I got that for use that at home where there’s no room to put a 30-inch screen anyhow, and it’s just fine.

Also, I figure that since Sun sent me a 30-inch-screen-capable connector, they must want me to get a 30-inch screen.


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From: Greg Phillips (May 22 2009, at 07:41)

I have the dual-link DVI adapter connecting a 17" MacBook Pro and a 30" cinema display. I've never had a problem with the setup – It Just Works – which probably means that the USB connector closest to the mini-DisplayPort on the MacBook is putting out plenty of power. The USB connector is also putting out signal just fine; my USB topology is MacBook to DVI adapter to display (which acts as a powered hub) to 7-port powered hub on the desktop. No glitches there either.


From: Tony Perrie (May 22 2009, at 10:45)

I had the same problem with my Dual-link DVI to mini-display port adapter. I thought my USB ports on the macbook pro were going bad.


From: Joachim De Lombaert (May 22 2009, at 17:03)

We have two of these adapters for use with 2 MacBook Pros, each of which has a third-party 30" display. We did have any initial setup problems; the displays began working correctly soon after we plugged them into the notebooks. However, at random intervals (sometimes every 5 minutes, sometimes every 6 hours) the picture will get messed up. At times the whole thing goes snowy; at other times, every other column of pixels seems to get phase-shifted somehow (text is painful to read, but images stay recognizable). We see this on both unibody MacBook Pros, but we've never had this issue with the same displays and non-unibody MacBook Pros. I hear this doesn't happen with 30" Cinema Displays, only third-party monitors.

I think it has something to do with tolerances in the adapters or the DVI cables (we're currently using the ones that shipped with the displays). We're going to try a number of different DVI cables (supposedly "higher quality" ones) to see if that improves things.

The fastest way we've found to recover from this issue is to press control-shift-eject on the keyboard to sleep the displays, wait 2 seconds, and then wake the displays again by moving the mouse.

Hopefully this information will be useful to you or people finding this post from search engines.


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May 21, 2009
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