Graphics support for SIS drivers

There doesn't seem to be a chipset driver included on SIS based graphics cards on completed installations.

On Live DVD sessions there seems to be a nice 1024x768 but when installation is complete the only resolution is 640x480.

The work around I'm using is to copy the attached xorg.conf (output below) into /etc/X11/ which gives 1280x768 @ 61Hz

The chipset lspci reports is:

VGA compatible controller: Silicon Integrated Systems [SiS] 771/671 PCIE VGA Display Adapter (rev 10)

xorg.conf:

Section "Device"
Identifier "Generic Video Card"
VendorName "Silicon Integrated Systems [SiS]"
BoardName "771/671 PCIE VGA Display Adapter"
Busid "PCI:1:0:0"
Driver "vesa"
Screen 0
Option "UseFBDev" "true"
Option "DPMS"
Option "ShadowFB"
Option "MaxXFBMem"
VideoRam 262016
Option "RenderAccel" "true"
Option "AllowGLXWithComposite" "true"
Option "backingstore" "true"
Option "AddARGBGLXVisuals" "True"

EndSection

Section "Monitor"
Identifier "Configured Monitor"
Vendorname "Generic LCD Display"
Modelname "LCD Panel 1280x800"
HorizSync 20-107
VertRefresh 50-185
modeline "800x600@56" 36.0 800 824 896 1024 600 601 603 625 +hsync +vsync
modeline "800x600@60" 40.0 800 840 968 1056 600 601 605 628 +hsync +vsync
modeline "1280x768@60" 80.14 1280 1344 1480 1680 768 769 772 795 -hsync +vsync
modeline "1280x720@60" 74.48 1280 1336 1472 1664 720 721 724 746 -hsync +vsync
modeline "1280x800@60" 83.46 1280 1344 1480 1680 800 801 804 828 -hsync +vsync
Gamma 1.0
EndSection

Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
Defaultdepth 24
SubSection "Display"
Depth 24
Virtual 1280 768
Modes "1280x768@60" "1280x720@60" "800x600@60" "1280x800@60" "800x600@56"
EndSubSection
EndSection

Section "Module"
Load "dri"
Load "dbe" # Double-Buffering Extension
Load "v4l" # Video for Linux
Load "extmod"
Load "type1"
Load "freetype"
Load "glx" # 3D layer
Load "GLcore"
Load "i2c"
Load "bitmap"
Load "ddc"
Load "int10"
Load "vbe"
Load "speedo"
Load "record"
EndSection

Section "DRI"
Mode 0666
EndSection