Mac Pro (Early 08) - USB or peripherals?

This is something I've been wondering for a long time.

I seem to have a lot of screen-related issues with the Pros that I sit in front of in the main. Brightness controls going haywire displays not turning on, etc. There is also the odd attached USB device lockup, but I'd been putting this down to the devices themselves and the occasional, app-level instability of Leopard.

More recently though, I've been seeing a pattern that's leading me to suspect the Pro's more than the peripherals. Is there a documented case of possible USB hub connection issues in (fully patched) 2008 Pros?

The most frequent issue is monitors not behaving as expected when the system is booted until the monitors themselves are unplugged from power. There are also less frequent but present problems where iPods lock up, keyboards stop working, etc. I can't really abstract the problem down to an OS issue or a hardware issue, but the need for me to unplug the monitors seems to indicate that there is some sort of USB initialisation issue - as with the other minor problems I experience with other monitor-connected USB peripherals. Since I only use multimonitor environments as far as my Pros are concerned, all USB connections are usually made from the backs of the screens.

So the big question is is this a screen USB hub fault, or a main-unit intermittent fault? All of the monitors I'm using have been to Applecare for one reason or another, although I'm not sure if they check everything in these repairs.

Can anyone else shed more light on this issue? It's pretty hard to replicate reliably and it's not been something I can go to Apple with any degree of certainty, yet the little minihoops I have with this problem (and oh so many other Apple issues, but that's by the by) irritate me immensely in comparison to my rock-solid, near-zero-such-issue, non-Apple environments which I also use daily.

The screen control issues only happen on boot. But not always. Normally the Macs are rebooted whenever they become non-responsive (depends on how heavily they are being used, but under heavy use almost certainly during the course of a day or two of such use), to apply updates or when the specific machine is not going to be used more than a couple of days.

Onyx is run regularly. The screens are calibrated.

Tesselator said:

Wow, I dunno man. Been on a Mac Pro for 3 years now (pretty much every day too :-/ ) and zero instances of what you mention. Loads and loads of USB devices too! Currently 9 devices connected.

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New Pros are released every year, and in my experience new problems come with them every year in addition to the fundamentally deficient (given the supposedly 'Pro' moniker) 'form over function' internal layout. I think this issue may be unique to the 08 Pros.

DualShock said:

Hmmm. Sounds similar to the problems I've had with my Cinema Display, documented here. I had the display repaired, but oddly enough the issues have returned.

Not only that, it appears to be a common issue, according to this thread at Apple's discussion boards. People are saying it's related to 10.5.6. In fact, the issues I started seeing seemed to happen after I installed 10.5.6 also.

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Some of those are identical to the issues I'm having. The thing is that I had this issue since with the first of the 08 Pros. Interestingly I can't really recall having it during summer, although that could have been because I was not on the Pros as often. I know that I've definitely had continual occasionally recurring issues of this on all the Pros that I currently use on a frequent / occasional basis (all '08).

All my current Pros for work and home are '08 models. I sold a good number of my '07-08 Pros last year along with the then-working monitors, and almost all of the monitors I have now are ex-faulty monitors that we let pile up for a while, but finally had repaired late last year - a mix of 23's and 30's, mostly refurb replacements due to panel or other problems.

All of the machines are running fully patched Leopard, and all have a range of factory-shipped video cards - ATI, 8800 and Quadro, either singly or a triple/quad monitor supporting combo.

The fact that it's happening with multiple from-new + refurb monitors and multiple machines means that the only thing I can put my finger on is really something to do with the behaviour of USB ports on the '08 Pros. But is it hardware or software? I dunno. The screen is certainly the most affected part, but odd USB behaviour is not completely alien to the Pros either.

I'll have to keep an eye on that and related threads. Thanks for the pointer.