I use NETBSD 1.4 and XF68_FBDev (Frame Buffer XServer) on Atari Falcon.
I have a Atari monitor SC1435 (VertRefresh 50/60 Hz, Horizontal 15.6/15.7 kHz)
I choose resolution under TOS (768x480, overscan) and I boot NetBSD.
When I start X, I always have the resolution I had when I boot NetBSD.

Is it possible to change the resolution (different from booting) when I start X?
My XF86Config file is:
I use in Section "Monitor":
 HorizSync 15.6-15.7
 VertRefresh 50-60
 Modeline "640x400" 25.175 640 664 760 800 400 409 411 450
 Modeline "320x200" 12.588 320 336 384 400 200 204 205 225 Doublescan
When I redirect the output of startX in a file, I have:
(--) FBDev: Mode "640x400" needs hsync freq of 31.47 kHz. Deleted.
(--) FBDev: Mode "320x200" needs hsync freq of 31.47 kHz. Deleted.
(--) FBDev: Width 768, Height 480, Depth 4
What values are correct for "640x400", "768x480" in the Modeline syntax ?