Has anyone else run into a similar situation to this, or have hardware that they can try to replicate with?
I have a Radeon 4770 in my system and up until two weeks ago, I had my primary monitor hooked up via a DVI->VGA adapter, and a second LCD hooked up directly via DVI.
When the system starts, the DVI monitor always got detected as the primary no matter which output of the video card it was attached to, which was annoying, but not the problem I'm asking about here.
I'm running Lucid right now, and whenever I slept the computer, waking the machine up from sleep would work fine on the DVI screen, but the VGA screen would never actually wake up. It would just stay either as a black screen, or it might have even stayed in DPMS off mode.
Kernel is stock Lucid from their development tree, but I'm also using X/Mesa from the xorg-edgers PPA. I'm assuming that upgrades the DRM modules as well, but I'm not sure offhand.
I'm assuming that there's some weird corner case that might exist in the kernel DRM code that doesn't re-initialize the analog output if you're running two displays in mixed mode (1 via VGA adapter, 1 via DVI), but I haven't had time to actually dig into the source yet, and like I said, I switched my setup two weeks ago to remove my KVM, so now both monitors are hooked up directly via DVI.