Hi shyamjith,
Check your Xorg.conf should match one of the following cases:
_______________
1) Vivante driver:
Section "Device"
Identifier "i.MX Accelerated Framebuffer Device"
Driver "vivante"
Option "fbdev" "/dev/fb0"
Option "vivante_fbdev" "/dev/fb0"
Option "HWcursor" "false"
EndSection
Section "Screen"
Identifier "Default Screen"
Device "i.MX Accelerated Framebuffer Device"
EndSection
Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
EndSection
_______________
2) fbdev:
Section "Device"
Identifier "Generic Framebuffer Device"
Driver "fbdev"
Option "fbdev" "/dev/fb0"
Option "HWcursor" "false"
EndSection
Section "Screen"
Identifier "Default Screen"
Device "i.MX Accelerated Framebuffer Device"
EndSection
Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
EndSection
as well chek /var/log/Xorg.0.log to see if there were any initialization errors that occurred at startup.
Hope this helps