Created attachment 15980 [details]
xorg log file

2D source is git tip.
platform: 915GM

I change the mode to 720x400. If the panel-fitting mode is center and full, display is OK.
If the mode is full_aspect, screen is totally black. then I change the mode to center, display become OK.

output of "xrandr -q":

Screen 0: minimum 320 x 200, current 720 x 400, maximum 1024 x 1024
VGA disconnected (normal left inverted right x axis y axis)
LVDS connected 720x400+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0 +   85.0     75.0     70.1     60.0
   832x624        74.6
   800x600        85.1     72.2     75.0     60.3     56.2
   640x480        85.0     72.8     75.0     59.9
   720x400        85.0*
   640x400        85.1
   640x350        85.1
TV connected (normal left inverted right x axis y axis)
   1024x768       30.0 +
   800x600        30.0
   848x480        30.0
   640x480        30.0

The machine has no TV connected, this is another bug:)

Reproduce steps:
xrandr --output LVDS --mode 720x400
xrandr --output LVDS --set PANEL_FITTING full_aspect