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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Notebooks > MacBook Pro and DVI KVM Switch Problem

MacBook Pro and DVI KVM Switch Problem
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newmacuser2006
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Nov 24, 2006, 11:44 PM
 
I have a new MacBook Pro laptop, 1st gen, with a 17" display.

The setup is connected to an HP f2105 via an IO Gear DVI/USB KVM.

When I switch from the Mac to another computer, and then switch back, the screen always turns blue and then comes back after a few seconds.

Sometimes, it does not come back for several seconds or even minutes.

Sometimes, it does not come back at all.

I have tried hitting the F7 function key and this can bring back the display. I have been forced to shut off the Mac a couple times.

After much testing, I have found when I use a lot of RAM or CPU, it's more likely that switching will lead to a problem. For example, running some DivX encoding jobs and I can't switch.

I also found out that the IO Gear tells the Mac that the monitor is 1024 X 768 while the screen is not focused.

My thought is that the Mac screen detector detects the screen resolution change when I switch, but that during times of high resource usage the process which changes the screen can't run or it runs very slowly.

Does anyone have an idea of how to fix the issue? This is my first venture into Mac land and I would like everything to work very well.
     
ibook_steve
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Nov 25, 2006, 02:05 AM
 
"I also found out that the IO Gear tells the Mac that the monitor is 1024 X 768 while the screen is not focused."

I think this is the key. The KVM should either detect the display correctly when not focused or not detect it at all. Does it call it "VGA Display" or "Color Display" when not focused? I think your KVM may be the problem. CPU usage should really have no affect on such a (relatively) simple process.

With my old G4 tower going to a second display through the KVM, when not focused, the G4 still thinks that that the second monitor is attached, preventing a required mode change whenever switching the KVM. I don't know if this behavior persists in newer machines, but it would prevent your problem.

Steve
     
newmacuser2006  (op)
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Nov 25, 2006, 08:54 AM
 
I am going to contact IO Gear next week, and I'll post up the results.

- I also found that this effect troubles other users of ATI graphics cards.
- I am trying out the little program "SwitchResX" and so far it has helped quite a bit.

Thanks!

PS I have the latest firmware update.

You know, before the firmware update it was MUCH worse. Even though my IO Gear is reporting a low resolution, that still does not explain why it takes so long for the Mac to resync.

Does anyone know how the firmware affects sleep and wake up, or screen detection?
     
   
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