xrandr only 480x640 in 2008.8 testing base image

[Cédric Berger]

Hi,
In 2008.8 testing base image, I cannot switch screen resolution :

root at om-gta02:~# xrandr -s 240x320
Size 240x320 not found in available modes

root at om-gta02:~# xrandr
Screen 0: minimum 480 x 640, current 480 x 640, maximum 480 x 640
default connected 480x640+0+0 (normal left inverted right x axis y
axis) 0mm x 0mm
   480x640         0.0*


is there something else to install, or where are these supported modes
configured ?