At first site - it was a simple task. But in fact there are few important specifications.
Both Mac Pro have different video cards:
First is macPro 2008 - have GF 8600 with two DVI outputs, second is MacPro late 2009 with GF120 - it has one DVI and one mini DisplayPort.
On the other side is Apple LED Cinema Display 27" and it have only mini Display port connector (M). This is the main problem to connect this display to any computer except those which has latest video cards with mini display port.
I think it was a very stupid idea to release a new generation of displays that are worse then previous generation. Lame connectivity options, pathetic LCD matrix that make it unusable for professional photo and video works.
So, back to our task, I searched for ready solution but nothing is available (at least at this time). There are different KVM solution - even latest ATEN products that can switch two computers with mini Display ports - but in my case I need not only switch between two computers but also convert signal from DVI to DP.
I start chain in reverse order since there are ATEN KVMs for DVI connections I decided to use one and then just convert DVI to mini DisplayPort.
The most simple part was to chose DVI-to-miniDP converter - Atlona AT-DP200. Its not cheap but its the only quality solution to convert signal and it pass through EDID information - to let computers detect display to select correct desktop resolution.
Next I need to select DVI KVM. I have it mind that 27" display have a very high desktop resolution - 2600x1400. So it requares DualLink DVI connection. I looked few Aten products and the only one that appers to work fine is
Aten CS-1782 (a) - both 1782 and 1782a work fine - the "a" version only able to work with 3D displays and its not important in my case.
It also have USB port on back side to power up
the DVI converter!
Also you can connect USB input from display to another USB port on the back side. Connect keyboard and mouse chain to Cinema display USB ports to make easy cable management. And finally you got additional USB port on front panel of Aten switch.
After to connect all cables - power on computers and enjoy simple switching between to computers with large display and extreme resolutions!
Well, to be honest there is one thing you have to remember - display turns on not so fast as when it connected directly to Mac. It takes time when Mac detects display through this chain of switch and converter. So its normal when picture on display appears when desktop start loading -near the end of booting process! When under some circumstances you do not have any picture on display try to press "Reset" button on converter- it happens sometimes especially when computer waking from standby mode.