Touchscreens (mutouch) & multiple heads

[Michael Smith]

Hi,

I have an Intel 915GM with two heads, each 800x600. One head feeds a 
touchscreen using the mutouch driver. Touchscreen input is being scaled 
by the total screen dimensions (1600x600), rather than just the 800x600 
part of the display that is connected to the touchscreen.

In the past I would have hacked up the mutouch driver to add overrides 
for ScreenWidth and ScreenHeight. I understand the X server now handles 
conversion of raw coordinates (in dix/getevents.c?), and the mutouch 
conversion_proc is no longer called.

Where is the right place to add a way to override the screen width used 
for converting raw coordinates? Or is there already a way to do this?

Section "InputDevice"
         Identifier "touchscreen_serial"
         Driver "mutouch"
         Option "Device" "/dev/ttyS1"
         Option "BaudRate" "2400"
         Option "InputFashion" "Touchpanel"

         Option "DebugLevel" "9"
         Option "ScreenNo" "0"
         Option "MinX" "0"
         Option "MaxX" "16350"
         Option "MinY" "16350"
         Option "MaxY" "525"

         Option "Name" "MUTOUCH:TOUCHSCREEN"
         Option "ReportingMode" "Scaled"
         Option "SendCoreEvents" "on"
         Option "Type" "Finger"
EndSection

Thanks!
Mike