Problem with NVIDIA graphics card: Solved?

Posted by Pierre Igot in: Macintosh
July 13th, 2009 • 9:27 am

A month ago, I wrote about a problem I was having in Mac OS X where the entire UI would freeze (except for the mouse pointer) or windows in a specific application (typically Preview) would become scrambled. At the time, the console and crash reporter logs seemed to indicate that it was a problem related to my Mac Pro’s NVIDIA graphics card, with a recurring “channel exception” error that a number of other Mac OS X 10.5 (Leopard) users seemed to be experiencing as well.

Two weeks ago, I wrote that I had received some feedback not just from Betalogue readers by also from Apple itself via the Bug Reporter.

The feedback from users suggested, among other things, that I open up my machine and make sure I didn’t have any build-up of dust that could cause ventilation problems.

The feedback from Apple was basically instructions on how to capture more information on the problem in order to try and better identify its cause. Since I was able to use ssh from another machine to log in remotely even when the Mac Pro was frozen, the Apple rep suggested I collect the “stack information” using /usr/libexec/stackshot.

I asked for more details about the use of this command and I was given the following instructions:

Please try “sudo /usr/libexec/stackshot -it” without the quote.

The fact is, however, that, ever since I followed my readers’ suggestions and opened the Mac Pro to inspect the NVIDIA graphics card and remove any dust that I might find, I haven’t experienced the problem once.

It’s now been several weeks, and I haven’t had a single UI freeze or case of scrambled video signal in Preview.

It is, of course, hard to say for sure what the problem was and whether I have managed to fix it.

The truth is that, when I opened up the machine to clean it up, I didn’t find much dust anywhere. I did find some, but not anywhere near the NVIDIA card. I still took the card out and got rid of the minor amount of dust that I could find. I also took out the two RAM cards, and the four internal hard drives I have in there. I cleaned everything I could clean, even if it objectively didn’t amount to much. And I reassembled everything carefully.

Is that what fixed the problem? Was it a minor dust problem that was causing the NVIDIA card to overheat and therefore exhibit these problems in Mac OS X? I am afraid I cannot say for sure. The weather has certainly not gotten any cooler, so there is no reason to suspect a drop in overall temperature that would have masked the problem.

The other thing to keep in mind is that I am part of the AppleSeed program for Mac OS X 10.5.x software updates, which means that I always get early builds of the next incremental Mac OS X update. When most of the Mac world is using Mac OS X 10.5.x, I am usually running an early build of Mac OS X 10.5.x+1. So for the past few weeks I have been using early builds of Mac OS X 10.5.8. I cannot entirely rule out the possibility that Mac OS X 10.5.8 might contain a fix for this problem.

The feedback from Apple didn’t seem to indicate that they felt it was a software problem that could be addressed in a system update, but you never know. Apple’s communications system is far from perfect and it’s quite possible that some of the Bug Reporter staff isn’t aware of a bug that is in the process of being addressed by Software Update developers.

For those other Mac users who are experiencing “channel exceptions” with their NVIDIA cards in Mac OS X 10.5, I am afraid I cannot be of much more help. If you have cleaned everything and are still experiencing the problem, all I can suggest is that, when the problem reoccurs, you use the instructions above to log in remotely and collect the “stackshot” information that Apple seems to need in order to be able to further investigate the problem. Then submit a detailed bug report with the information via Bug Reporter, and hope for the best.

Remember: The higher the number of reports that get submitted via Bug Reporter, the higher the likelihood that Apple’s staff will take the problem seriously and do something about it. Just because the problem seems to have disappeared in my case, it does not mean that there is no problem in Mac OS X 10.5’s NVIDIA graphics drivers.

(In order to be able to use Bug Reporter, you need an ADC membership. The basic membership is free and you don’t need to actually be a Mac developer in order to get one.)

One Response to “Problem with NVIDIA graphics card: Solved?”

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