Edit the Xserver.conf file to add the text -I -ffbDoDMA 4 to the
command line arguments section.  For example, if the command line
arguments section is in its initial default state, it appears as follows:
! you specify command line arguments here
args <
-pn
>
Insert the text -I -ffbDoDMA 4 after -pn as follows:
! you specify command line arguments here
args <
-pn -I -ffbDoD
>