Mini DisplayPort to Dual-Link DVI Adapter creates jumpy mouse cursor

My new Mini DisplayPort to Dual-Link DVI adapter was just drop shipped direct from China. I installed it yesterday and have been using it all day today. No problems at all. Also, although it uses one USB port, it has a pass through so the USB hub in the Cinema Display works and still leaves an empty USB port on the MacBook. Your issues may be either defective units or a problem with the Pro MacBook model. Hope this helps.

I received my dual link adapter yesterday and installed it to my 30" display.

Under normal operation (all the 10.5.6 native applications & VectorWorks 2008), I have no issue with the USB socket on the adapter. Under normal operation, the processors stay reasonably warm but not hot and the fans don't get too excited.

While gaming (sad old, antiquated RTCW), everything gets hot--which is reasonable to expect. Under this condition, the USB socket on the adapter works fine initially, but then becomes erratic as the MBP gets hot. Input devices (external mice, external keyboards) attached to the adapter's USB socket quickly stop responding AS THE PROCESSOR TEMPERATURE INCREASES. Once the temperature subsides and I unplug-then-replug the adapter's USB plug directly to the MBP's USB sockets, the adapter USB socket is again functional.

I tried this with a USB hub (running several simultaneous devices) plugged to the adapter USB socket, as well as with individual input devices plugged to the adapter USB socket. Regardless of the number of devices attached, whether one or many, the adapter USB socket fails on graphic intensive work.

Input devices plugged into MBP's other native USB socket worked properly throughout these experiments. So, I switched the adapter's USB plug into the MBP to the other socket and repeated the experiments. Same results as before.

Throughout all these USB issues, the DisplayPort-to-DVI part of the adapter worked fine, as expected. Though the USB socket crashed or stopped responding, the display parts all worked fine.


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It seems to me that the USB-bus-powered dual link adapter has trouble when data & power needs to travel in two directions. Which is to say, when the USB portion of the adapter is not in use +as a data input socket+, I notice no USB issues whatsoever with the adpater. However, when the adapter's USB socket is also used for data input (from an external mouse or keyboard), in addition to powering the adapter itself, the USB socket's functionality is lost.

Nonetheless, it's very frustrating to have pre-ordered and waited for months, only to have the latest greatest MBP unable to reliably preform graphics operations it's advertised to handle with ease.

Benn,

Even with the USB plug on the adapter not used, I still get the erratic mouse behavior. I verified this by unplugging the USB cable from the monitor and plugging it directly into the computer. I then tried removing ALL USB connections (except for the adapter) and the problem persists.

However, I think there may be something to the temperature thing. I eventually got so frustrated that I went back to using my old laptop. The next day, I turned my new MBP on (unused for a day) and saw none of these issues. Of course, now, they're back. I can only conclude that it (the computer, not the adapter) just needed to warm up for a while. Note: I have two of these adapters, and the problem exists with each one (in other words, I can't plug in a "cold" adapter and have the problem go away).

Here's my "test" for this problem:

Move the mouse around in a circle on the screen at a normal, but continuous speed. At about 3-4 seconds, the pointer (cursor) will jump an inch or two on the screen.

Can any of you who say you have no problems give this a try, preferably with a "hot" machine?

Thank you, krypttic, for reiterating that your USB issues are occurring within the MBP itself when used in conjunction with the dual link (DL) adapter.

Ugh! I'll be calling Apple tonight.

Like you, I pre-ordered the DL adapter and patiently waited. Meanwhile (up until yesterday), I purchased and temporarily was using a DisplayPort-to-DVI adapter. The MBP could only support 1600x1200 across this "powerless" adapter, but as a temporary solution, it served its limited purpose. While using this "powerless" DP-to-DVI adapter, I had no issues whatsoever, regardless of heat. You betcha, I have been using my MBP for normal operations (lite graphics work) and gaming (graphics intensive) for months now, all without incident.

These current USB failures never once occurred with the "powerless" adapter. So naturally, when I got the USB-bus-powered, DL adapter, I expected no issues. Immediately upon using the DL adapter with graphic intensive work, it takes absolutely no more than 4 minutes before the USB input response becomes erratic (jumpy mouse), and is nonfunctional (frozen) within 1 minute thereafter. Simultaneously, the MBP has progressed from warm to hot.

There's no way to test the DL adapter with an external power source (such as the iPod AC adpater) without voiding the warranty.

Open Console and check your system.log. I have multiple, repeating messages that say:

Dec 23 18:42:43 Krypttics-Computer kernel[0]: dp events: 0x04
Dec 23 18:43:13: --- last message repeated 5 times ---

It will cycle this message over and over until I disconnect the adapter.

Someone else with the adapter has seen this now too:

http://discussions.apple.com/thread.jspa?messageID=8676662#8676662

I’m having those same system log messages. Perhaps I just haven’t triggered the other problem yet. I was in Windows for hours today without any noticeable mouse issues. I hope that this gets fixed as I was a little miffed at the two month wait as well. Sometimes leading edge tech really is bleeding edge tech...

SecondAct:

Can you please try the "move the mouse around in a circle" thing (see my post above) when you're back on the Mac side and see if you notice stutters every few seconds?

Thanks.

I just tried the circle test on a relatively cold machine (I use a coolpad and I have the low power MacBook model). I did notice a small jump, as if the mouse stopped responding for a moment then tried to jump back to the correct position. Sorry I doubted you all. I’ve hated the mousing since OS X changed the Classic OS parameters so I just chalked it up to normal bad mousing experiences. Consider me converted to the idea that there is a driver problem. I will repeat the test in Windows XP and see if I can repeat the problem.

I think this may be a 10.5.6 issue. I just received a replacement computer from Apple and booted it up with the pre-installed system (10.5.5) and there was no jumpy mouse and no messages in system.log. I then put my old hard drive in the new computer (with 10.5.6 and all the current updates) and the problems were there again.

By the way, a new mouse driver isn't going to fix this. I installed SteerMouse and the problem remains. I think all these writes to the log file are stealing time from the mouse connection. Six entries every 30 seconds sounds excessive and I saw no such entries with the fresh 10.5.5 installation.

I have submitted two bug reports with Apple. Hopefully the rest of you do too so they can but this on their list of fixes.

I agree. I tested my setup with the circle drawing test in Windows XP and the problem doesn’t manifest there. I’m guessing Mac OS driver issue. Happy Holidays everybody!

Just adding a "Me Too". I have a MB 2.4ghz connected to a 30" monitor. My mouse jumps about an inch every once in a while. I can't figure out a pattern.

I have a Samsung monitor (in a different office) that shows static on waking from sleep on the same MB.

I'm not so impressed with Displayport.

UPDATE:
After some time on the line with the first Applecare guy he up-transferred me to a product specialist who read this whole thread and then sent me a capture data program and asked me to run it and email him the results back. He said, (but didn't promise), that he expects Apple would have a fix for it within 30 days, although I'm sure we're all hoping it comes down the pipe faster than that.

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