Multiple screen Snow Leopard upgrade issue

[nightfly13]

So I finally got around to repartitioning my main system SSD to GUID and then upgrading to SL.

Worked pretty seamlessly, but one of my 4 displays has gone all black. I use 2 video cards, and I have 2x 1080p monitors on a GeForce 7300 (and a 30" and projector running from the 8800) and one of the 1080p monitors is working perfectly (typing on it now) but the other one, which flanks my 30" on the opposite side, is all black... I know what you're thinking - but the weird part is when I drag a small window from any program over to that screen - I just see the mouse go over, not the window. It's like it's not drawing anything over there - except the mouse.

Any thoughts? System Profiler sees the two screens, and that both are rotated, tried changing resolution...

 

[J the Ninja]

Have you tried the good old "Disconnect and reattach the display" trick?

 

[nightfly13]

Yes I did, although that was from the Monitor - not from the back of the Mac Pro. The issue isn't that the monitor's not recognized.. anyway I can reach around and try that with some difficulty - but worth troubleshooting.

I discovered that when I turn off the rotation (standard from 90 degrees) it shows up fine. Curious thing is, the other monitor is rotated 270 degrees and working perfectly. They are the same model monitor, plugged into the same video card. I tried the 'black' monitor at 270 and same effect (black but mouse is visible) but, of course, upside down ¡¡¡¡

 

[nightfly13]

Hmm yes, as I feared, disconnected and reconnecting from the back of the pro didn't do anything. It saw it was gone (remaining screens flash blue) and then found it and produced the same black+mouse problem.

 

[gotzero]

I had a similar issue a long time ago with 10.5. I ended up disconnecting all but the main display, modified all of my settings, and then connected one more display at a time until everything was working.

It took about an hour, and I still do not understand what if anything I fixed, but all panels are running correctly now.

 

[nightfly13]

I had a similar issue a long time ago with 10.5. I ended up disconnecting all but the main display, modified all of my settings, and then connected one more display at a time until everything was working.

It took about an hour, and I still do not understand what if anything I fixed, but all panels are running correctly now.

Hmm I'll give it a go, I guess. Although I'm toying with the idea of just turning the problematic display back to the original orientation. Having 1 1920 pixel high display for Safari is probably enough, although it would mean a little more head movement side to side. I'll keep fiddling.

 

[nightfly13]

Hmm well I swapped the 720p projector for the 1080P monitor, turned it around and everything's fine.

I guess the 8800 is meant to run 2x 30" monitors, so a 30 and 1080p probably don't stress it too hard.

Weird issue, but solvable - I guess.