--- Comment #16 from Stefan Dirsch email@example.com --- Ok. Apparently with your gfx card, you have no framebuffer device at all. No idea why. Maybe it's time to get rid of this gfx card. Seriously.
[ 164.682] (EE) Unable to find a valid framebuffer device [...] [ 164.683] (DB) xf86MergeOutputClassOptions unsupported bus type 0 [...] [ 164.698] (EE) FBDEV(0): FBIOPUT_VSCREENINFO succeeded but modified mode [ 164.698] (EE) FBDEV(0): mode initialization failed
And apparently framebuffer on your Matrox AGP cards work. There is no KMS driver for Matrox G400, and mga X driver no longer work with current kernel.