$ grep -i geode /tmp/xorg0log2.txt
[ 80.558] (==) Matched geode as autoconfigured driver 0
[ 80.559] (II) LoadModule: "geode"
[ 80.560] (II) Loading /usr/local/lib/xorg/modules/drivers/geode_drv.so
[ 80.592] (II) Module geode: vendor="X.Org Foundation"
[ 80.607] (II) GEODE: Driver for AMD Geode Chipsets: Geode LX, Geode GX
[ 80.674] (II) GEODE(0): Creating default Display subsection in Screen section
[ 80.674] (==) GEODE(0): Depth 16, (==) framebuffer bpp 16
[ 80.674] (==) GEODE(0): RGB weight 565
[ 80.674] (==) GEODE(0): Default visual is TrueColor
[ 80.674] (==) GEODE(0): Using gamma correction (1.0, 1.0, 1.0)
[ 80.674] (==) GEODE(0): No DCON is present
[ 80.674] (II) GEODE(0): VSA Panel Mode is: 800x600, pixel clock freq(kHz) is 40000
[ 80.674] (II) GEODE(0): LX output options:
[ 80.674] (II) GEODE(0): CRT: YES
[ 80.674] (II) GEODE(0): PANEL: YES
[ 80.674] (II) GEODE(0): DCON: NO
[ 80.674] (II) GEODE(0): VGA: YES
[ 80.697] (II) GEODE(0): Primary V_BIOS segment is: 0xc000
[ 80.739] (II) GEODE(0): Output default has no monitor section
[ 80.741] (II) GEODE(0): I2C bus "CS5536 DDC" initialized.
[ 80.742] (II) GEODE(0): Printing probed modes for output default
[ 80.742] (II) GEODE(0): Modeline "800x600"x60.3 40.00 800 840 968 1056 600 601 605 628 -hsync -vsync (37.9 kHz e)
[ 80.742] (II) GEODE(0): Output default connected
[ 80.765] (II) GEODE(0): Using exact sizes for initial modes
[ 80.765] (II) GEODE(0): Output default using initial mode 800x600
[ 80.765] (II) GEODE(0): Using default gamma of (1.0, 1.0, 1.0) unless otherwise stated.
[ 80.765] (--) GEODE(0): Virtual size is 800x800 (pitch 0)
[ 80.765] (**) GEODE(0): Driver mode "800x600": 40.0 MHz (scaled from 0.0 MHz), 37.9 kHz, 60.3 Hz
[ 80.765] (II) GEODE(0): Modeline "800x600"x60.3 40.00 800 840 968 1056 600 601 605 628 -hsync -vsync (37.9 kHz e)
[ 80.765] (==) GEODE(0): DPI set to (96, 96)
[ 80.803] (II) GEODE(0): vgaHWGetIOBase: hwp->IOBase is 0x03d0
[ 80.805] (II) GEODE(0): Geode LX video memory 1600000 bytes at 0xb5906000
[ 80.805] (II) GEODE(0): LX video memory:
[ 80.805] (II) GEODE(0): Display: 0x190000 bytes
[ 80.805] (II) GEODE(0): Compression: 0x6a400 bytes
[ 80.805] (II) GEODE(0): Cursor: 0x3000 bytes
[ 80.805] (II) GEODE(0): ExaBfrSz: 0x40000 bytes
[ 80.805] (II) GEODE(0): EXA: 0x12c2c00 bytes
[ 80.805] (II) GEODE(0): FREE: 0x0 bytes
[ 81.209] (==) GEODE(0): Backing store disabled
[ 81.213] (==) GEODE(0): DPMS enabled
[ 81.213] (II) GEODE(0): RandR 1.2 enabled, ignore the following RandR disabled message.
[ 83.161] (II) GEODE(0): Setting screen physical size to 211 x 158
[ 84.091] (II) GEODE(0): vgaHWGetIOBase: hwp->IOBase is 0x03d0
[ 84.093] (II) GEODE(0): Geode LX video memory 1600000 bytes at 0xb591a000
[ 84.093] (II) GEODE(0): LX video memory:
[ 84.093] (II) GEODE(0): Display: 0x190000 bytes
[ 84.093] (II) GEODE(0): Compression: 0x6a400 bytes
[ 84.093] (II) GEODE(0): Cursor: 0x3000 bytes
[ 84.094] (II) GEODE(0): ExaBfrSz: 0x40000 bytes
[ 84.094] (II) GEODE(0): EXA: 0x12c2c00 bytes
[ 84.094] (II) GEODE(0): FREE: 0x0 bytes
[ 84.414] (==) GEODE(0): DPMS enabled
[ 84.414] (II) GEODE(0): RandR 1.2 enabled, ignore the following RandR disabled message.
[ 84.678] (II) GEODE(0): Setting screen physical size to 211 x 158
..would seem to indicate that things should work - did you try googling to see if an xorg.conf snippet is needed for your specific hardware?