Green lights across the board, but HMD stays dark [solved]

I've been trying to get the Vive to work for a while now, but haven't had any success so far. I think the root issue has always been that the HMD advertises itself as a 1280x720@60Hz display to Windows whenever I plug it in, and as a result the VR monitor can't find it. I was generally getting messages that the HMD was contacted via USB, but not found as a display.



Today I tried something bold and made a custom video signal for the HMD via Nvidia's control panel, using 2160x1200@90Hz and standard GTF video timings. That resulted in green lights in VR monitor across the board (after uninstalling USB devices a few times), and a green light on the left side of the HMD, but the HMD screen itself stays dark.



I can run the Hello VR application and see the field of cubes on the main display, and it reacts properly to moving the HMD or moving the controllers, but nothing is displayed on the HMD.



The HMD is connected to the breakout box via the custom cable, blue end plugged into the HMD, and then from the breakout box to a mini HDMI port on my GPU, via the regular HMD cable that came with the Vive.



I'm on Windows 8 professional for this, and am using an Nvidia GeForce GTX 580 that I had lying around, with up-to-date drivers.



Anybody have any suggestions?



Thanks in advance!



Edit: It's working now. The issue was bad Extended Display Identification Data (EDID) in the headset's firmware. I had to set up a custom video format, using precise timings provided by a friendly Valve engineer, and now all is good. Thank you all for your suggestions!