Re: 9746 and 9755 drivers do not detect panel resolution correctly anymore
According to the EDID in your DFP, both 1400x1050 & 1440x900 are valid native modes. Try adding the following options to the Device section of xorg.conf:
Option "ExactModeTimingsDVI" "true"
Option "ModeValidation "NoDFPNativeResolutionCheck"