I have Zaurus SL-C3200, which has native screen resolution 480x640, but the resolution native to users is 640x480. That is why the default position of the screen is changed by command line arguments:
Xfbdev -br -pn -dpi 200 -rgba rgb -screen 480x640@270 :0 -noreset

But when program asks for xrandr values, some values are returned using the native screen coordinates, other values are returned using rotated coordinates.

For example icewm guesses full size window badly and full screen windows has swapped sizes.


Screen 0: minimum 480 x 640, current 640 x 480, maximum 480 x 640
default connected 480x640+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   480x640         0.0* 

Work-around:
Xfbdev -br -pn -dpi 200 -rgba rgb -screen 480x640 :0 -noreset
xrandr -o right

The result is exactly the same screen orientation, but xrandr returns correct values. Now it is clean, that the screen is rotated and applications work correctly.

Screen 0: minimum 480 x 640, current 640 x 480, maximum 480 x 640
default connected 640x480+0+0 right (normal left inverted right x axis y axis) 0mm x 0mm
   480x640         0.0*