Distro is Arch. GPU is discrete "NVIDIA Corporation G86 [GeForce 8400 GS] (rev a1)" (NV50 family) with VGA and DVI-I ports, monitors connected to both. The last provided kernel in the 3.8 series was 3.8.11, which worked fine. When running 3.9.{2,3} (provided) and 3.10rc2 (self-compiled), the VGA connected monitor does not get a signal.
Outside of X things seem normal, besides the blank VGA screen. When X is started with my normal user (setup to span screens) the machine locks up. When X is started with a dummy user (screens would be mirrored if they worked) it takes longer than normal (10-15 seconds) to initialize. The GUI tools ([XFCE] Settings > Display) indicate the VGA screen is present and active, but it remains blank. I also have no mouse pointer, though the mouse is active. This is meaningful because I think the pointer is supposed to be hardware accelerated.
I've compared kernel logs, systemd journal, and Xorg logs between 3.8.11 and 3.9.3 and nothing stands out. The only thing I've found that's remotely similar is
a kernel bug report, but unlike that case my /sys/class/drm/card0-VGA-1/status reads 'connected' in the problem kernels.
So, I'm looking for suggestions wrt filing a bug on the kernel bugzilla, which I've never done before. Do I have enough info to file a new bug? If not, what else could I gather?