Are there any other options?
Surely the video card knows when the signal it's generating isn't being consumed. I thought that was an FCC requirement, analogous to how sound cards don't generate a signal if there's no wire plugged in.
So assuming the video card knows, is this info available anywhere? Does the XFree86 driver feed it to any place inside X that I can query?
For the curious, I have a spare-ish computer running a monitor up in the corner of my room. When I turn the monitor off I want my slideshow application to pause so 1) it frees CPU for other tasks I occasionally run on the box, and 2) resumes the slideshow where it left off.
Sure, I could pause the app from over the network, but that's kinda inconvenient, especially when all the interface I need (a big plastic button) is already present.