I have an ongoing problem with my TV losing the signal from my HTPC. It is currently connected via HDMI. I am wondering if I go to a DVI to HDMI cable and separate audio cables if that will fix my problem. Does the DVI - HDMI carry 1080P without the need for any handshaking?
Will using DVI to HDMI fix my EDID\handshake issue
Does it lose sync while you're watching it or only when you do something like switch TV inputs or reboot the HTPC? If the former, I don't think going DVI to HDMI will help. What makes you say this is an EDID issue? HDMI and DVI are identical with respect to EDID, if that's the issue you may need a DVI Doctor from Monoprice. I have one and it works great!
The DVI Doctor magically(!) works as an HDMI doctor, but you'll need two HDMI to DVI cables. I go HDMI out of my HTPC, DVI into the DVI Doctor and HDMI into my receiver. No issues with the TV switching inputs (or even being on), and the audio is still passed through (including hi-def audio formats). This surprised me as I assumed the audio would be lost when converting to DVI, but it isn't.
Is your problem that you have to re-set your HTPC's resolution whenever you switch your TVs input away the back to your HTPC? I found both the Nvidia and Intel drivers detect this has occurred, and switches to a "safe mode" resolution (or back to single-display mode if you're running dual/clone as I am). It's not a loss of handshaking per se, it's a "feature" of the drivers. DVI Doctor will definitely fix this for you.
By an HDMI matrix setup, do you mean a powered HDMI splitter? If so, that won't help, unless the one you get has some sort of built-in EDID-saver.
I'm curious if the hack you linked to will work, though I use Intel graphics so it's no good for me. My guess is no, they're overriding the EDID but your situation is that there is no EDID. Worth a shot though if you can find an ATI equivalent.