Section "Device"
Identifier "g400"
Driver "mga"
Option "AGPMode" "4"
>>> VideoRam 32768 <<<<<<< this is the root of the problem
I had some cursors invisible; in the end it was the default cursor which was set incorrectly: What to see:
Xcursor.theme: Blue Xcursor.size: 100
/usr/local/share/cursors/xfree/ /usr/share/cursors/xfree/
; gtk-style-cursor-info
grep for gdk_cursor_new_for_display
-> GDK_SB_H_DOUBLE_ARROW
GDK_TOP_LEFT_ARROW GDK_SB_H_DOUBLE_ARROW
(map-numbers 0 152 (lambda (i) (default-cursor (get-cursor i)) (sleep-for 1)))