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Dual monitor problems on Dell GX620 USFF (GMA950)


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I just got started with OSx86 in the most dangerous way -- by buying a system off someone who already had it mostly working. So I didn't have to learn anything the hard way to get it installed! :-)


I've already monkeyed around with it enough to get sound working and to change my screen resolution (when I've only got a VGA monitor connected at least). But I can't get it to recognize that I've got 2 monitors attached and show something different on each.


I've got a Dell GX620 USFF, which has GMA950 graphics (i945 -- device ID 0x2772, revision 0x0002). It has a single DVI-I port, which I've connected to a VGA and a DVI-D monitor using a splitter cable.


I'm running iDeneb 10.5.6.


I can't say for sure whether the original owner replaced any of the relevant kexts with something non-standard. I've removed all video related stuff from com.apple.Boot.plist (which didn't change anything -- the former owner had inserted some nVidia related stuff -- I don't know why since there's no nVidia hardware in the computer, and it's not expandable, so he couldn't have removed or replaced anything.)


When I bring up System prefs/displays, it just shows one resolution and one color depth option (not a big deal), and no pane for arranging multiple monitors (is big deal!) They just both display the same thing.


I've seen a video of somebody running dual monitors with different contents on this same hardware, so I know it's possible. But a lot of searching hasn't turned up anything that works.


Any help anyone could give would be greatly appreciated!

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I'm making progress. Using "DSDT Editor", I created two dsdt.aml's -- one with both monitors attached and turned on, and one with just the VGA monitor attached. For both, I applied the DTGP and GMA950 desktop patches. And for the first, I also applied the GMA950 laptop patch. I know, I'm not on a laptop. But that was required to get it semi-working.


If I boot with the second dsdt.aml and BOTH monitors attached, the DVI monitor gets no signal after a certain point in the boot process, and the VGA monitor displays black, with the mouse pointer occasionally showing, but doesn't seem to be running properly (I can't shut the computer down using the keyboard).


If I boot with the second dsdt.aml and ONLY the VGA monitor attached, it comes up and I can switch resolutions on the fly (ie. it's a perfect single monitor setup).


If I boot with the first dsdt.aml and both monitors attached, the DVI monitor gets no signal after a certain point in the boot process, but the OS boots, the VGA monitor displays fine, and I can switch its resolution on the fly. (I had to monkey around a little to get the VGA monitor recognized as the primary monitor.) Also, the system thinks there are two monitors attached -- I can switch the resolution for the monitor that's not getting a signal, move the mouse there, etc. My Wacom table acts like the desktop is extending over to wherever I have the other monitor positioned.


Before I continue, a few tips for anyone considering doing stuff like this:


1) Have two partitions -- one with a known bootable OS, and one where you experiment. Use Carbon Copy Cloner to clone the good partition, and then monkey ONLY with the test partition until it works as desired. Then clone it back.


2) Before cloning a partition, open a Finder window and make it really big. That way, if you boot up and only the secondary monitor displays, you're sure to be able to navigate to system prefs. When you open system prefs, if it's on the invisible primary monitor, type "dis" and hit enter to open the displays panel. You'll find a "gather" button that'll bring the control panel for both displays onto the visible display. Drag the menu bar to the current display, and you'll be on the primary monitor.


Okay, so my question is, why the heck it turning off the DVI-D signal and just leaving the VGA signal going? How can I make it stay on? Anybody have any ideas?



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