Well, crmfb0 itself doesn't work. The system boots, but the display is
messed up: thin (1 pixel) dark red vertical lines on a black
background,
with 6 2-pixed white horizontal lines, starting a line 0.
This is weird, as if the graphics backend reads from different tiles
than the rendering engine writes to, or the rendering engine doesn't
render. Crmfb doesn't directly access any visible video memory - to
avoid having to deal with tile borders I have rasops draw into an off-
screen tile and then blit it into place. Maybe I should memset() it
with something recognizeable for testing.
Do the red lines disappear eventually?