Archive for March 6, 2009

Friday, March 6, 2009 [Tweets] [Favorites]

My 15-inch MacBook Pro and Mini DisplayPort to Dual-Link DVI Adapter

I’ve been enormously pleased with my 15-inch MacBook Pro in nearly all respects. The unibody, the screen, the graphics, the processor and RAM, the keyboard, the trackpad, the accessibility of the hard drive—all are big improvements over the 2006 model that I had been using.

The support for external displays, however, has been abysmal. Apple’s Mini DisplayPort to Dual-Link DVI Adapter costs $99, it was delayed for months, and it doesn’t work properly. Periodically, the display becomes distorted or snowy. The store reviews and discussion boards (1, 2, 3, 4) show that lots of people are seeing these problems, with both Apple and third-party displays.

In my case, with a Dell 3007WPF, the distortion occurs most often within 10 minutes of coming out of the screensaver. Sometimes it happens several times within a span of 5 minutes. Other times it happens only once a day. The average is about twice a day. Sometimes the display temporarily forgets its ColorSync profile until I open the Displays pane in System Preferences. Sometimes the display flickers. None of this happened when using the same display with the older MacBook Pro.

Apple’s support page recommends resetting the adapter by unplugging and replugging it. This temporarily fixes the major distortions, but lesser distortions (such as a vertical line pattern in areas of solid color) remain until the computer is rebooted. Of course, unplugging the external display causes Mac OS X to move all the windows to the internal display. After reconnecting the external display, I run an AppleScript to restore the windows to their proper positions.

The problem seems to be related to USB. It occurs less frequently when the adapter is the only device plugged into the Mac. Currently, I’m leaving the USB port next to the Mini DisplayPort vacant, I plug a USB hub into the far port, and I plug the adapter and all my USB devices into the hub. This has reduced the occurrences to the frequency described above. With both the adapter and the hub plugged into the Mac, the problem occurred much more frequently, making the computer almost unusable.

Apple shipped the adapter in December, and negative reports surfaced almost right away. I figured it wouldn’t be long before Apple found and addressed the problem, and I bought the MacBook Pro in January. For me, the problem first occurred on January 20. I called Apple, and the specialist had not heard of the problem before. He wouldn’t send me a replacement adapter, instead suggesting that I send both the MacBook Pro and the adapter to Apple for testing.

On January 26, Apple released an NVIDIA Graphics Update that “improves cursor movement when using the Apple Mini DisplayPort to Dual-Link DVI adapter with the Mini DisplayPort enabled MacBook Air, MacBook and MacBook Pro.” As the Mac was not in my possession at that time, I did not install the update. Apple later pulled it.

On February 5, I received the MacBook Pro back, unchanged. Apple said that both the computer and the adapter checked out and that they had not been able to reproduce the problem. I called Apple to find out what the next step was. Because all the tests had passed, they would not send me a replacement adapter. The representative I spoke with seemed to have never heard of DisplayPort. A higher-up product specialist said he would get in touch with engineering and get back to me.

On February 12, the specialist called back with some suggestions: reset the SMC and the PRAM, and delete various com.apple.windowserver plist files. This didn’t help.

On February 17, he called and sent some test programs I could run in order to gather information about my system. I did this and sent the log files to the Apple engineers.

On February 23, he called to say that engineering was now well aware of this issue and had been hearing other reports of it. They believe there is no hardware problem and that they’ll be able to fix it with a software update.

The current state of affairs is that:

Thus, the new MacBook Pros have been available since October, and there is still no reliable way to use them with a 30-inch display.

Update (2009-04-20): I’ve found that putting the display to sleep (by pressing Control-Shift-Eject) sometimes fixes the distortions. As this does not affect the window positions, I recommend trying it before unplugging the adapter.

Update (2009-10-03): Updating to firmware version 1.0.2 of the adapter has helped a lot.