Hey guys,
I don't think it's an adapter issue (vga or dvi) as I have the same issue with my D630 w/NVidia graphics, quad boot W7/W8/ML10.8.2/Ubuntu12.10.
I also have tried vga to dvi adapter, dvi cable alone, and lastly vga cable as it's originally configured (which works very well when booting to other 3 OS's).
Everything and all OS's boot as they should with no flags to set before any OS boot. (ML runs flawless)
What clmac means by "It just goes into sleep mode just before the Login screen." is that at boot whether at the apple screen or in verbose, right before it boots to the login screen the Laptop physically goes to sleep/hibernate mode thus also sleeping the monitor.
When my laptop is docked to the station the laptop will completely hibernate (visually confirmed by laptop activity LED's in sleep mode) and power everything down to sleep until undocked and power button pushed, then resumes login.
Anyone have any idea why it does this on the dock station?
