Monitor and MacBook Pro not on speaking terms anymore This one puzzles me.  I have this setup

[MBP]&lt;----[HDMI]----[HDMI-DVI Adapter]---->[BenQ FP222W]

When I plug in the monitor, the MBP detects it and the screen flashes like normal.  Likewise the monitor detects "Input: DVI" and the backlight comes on. Then nothing.
I can move windows to and from the blank screen (they don't display, but they do move there), and as far as my computer seems to know, it's connected.

But here's the weird part, I've tested every component and everything works:


Monitor with new laptop and same cable -- WORKS
Monitor with my laptop and DVI cable (DVI to displayport) -- WORKS
Different monitor with original cable -- WORKS
Different monitor with just HDMI cable -- WORKS
Monitor with VGA cable (VGA to displayport) from different computer -- WORKS
Monitor with DVI cable to different laptop -- WORKS


What am I missing?  I've verified that all the outputs on my laptop work, all the inputs on the monitor work, and all the cables work.  I'm out of ideas (and also curious to see what other people think).

Just to cover a few bases, I tried holding the cable at different angles, I tried leaving the monitor off (in case the gremlins inside can be killed with a lack of electricity), and the monitor was working on Friday Jan 2 (then I was gone all week last week, and it started being picky yesterday morning).
Reboot the Mac with the monitor cable connected. That sometimes fixes it.