Originally Posted by Glockpop
For people interested in plugging an DVI/HDMI source into this screen, keep in mind that physical connectors are not necessarily adequate for bridging two technologies, and that compatibility isn't always a two way street.
For example, Apple put DVI ports on its pre Mini DP Macs which supplied both VGA (analog) and DVI (digital) video signals. You could use an adapter to extract either VGA or DVI signals. Many models also provided Composite Video signals over the same physical port, so with the appropriate dongle, you could hook your Mac to a TV.
That doesn't mean that you can do the reverse, such as using a VGA-ony computer to drive a DVI display, just because you can find a cable with those physical connectors on each end. VGA is not forwardly compatible with DVI.
Similarly, just because some Macs provided Composite Video through the DVI connector didn't mean they all did. You can't extract signals that aren't there.
The current DisplayPort specification allows for "other" signals to be delivered over a DP cable, potentially audio or USB. Existing Macs apparently do not actually support either, so there's no way to plug MDP into HDMI and get both audio and video output. Audio just isn't there.
Additionally, Macs with MDP connectors don't just provide DP output. They also provide DVI and HDMI-compliant signaling, which is why you can plug in a dongle and export video from a MacBook Air to a DVI display or an HDMI TV.
That doesn't mean that a PS3 can generate a DP signal! Even if you can find an HDMI to DP cable, if the signal isn't being created, it won't be delivered (!).
Based on Apple's wording, video input features on the new 27" iMac allow for DP input, not whatever anyone might want to plug in. You can't wire a VGA connector to a MDP connector and expect your PowerBook G4 will drive the new display.
For the same reason, you will probably also not be able to simply plug in anything else you might want to see on your fancy display. While we're at it, also keep in mind that the resolution of the display won't magically be supported by devices that can only manage something less. To use the full resolution of the display, you have to use a connection technology that supports that bandwidth, which minimally requires dual DVI, HDMI, or DisplayPort.
And of course, it appears that only one of those will actually work.