How to enable DRI on Radeon 9500

[ppesci]

I want to test DRI module in my laptop.

In /var/log/messages say:

Avoiding DRI on Radeon R300+. Use 'allow_r300=1' module option to override

I go to xorg.conf and change

Load "dri"
in Module Section by:
SubSection "dri"
Option "allow_r300=1"
EndSubSection


but anyway DRI appear to be disabled.
typing:
grep "Direct rendering" /var/log/Xorg.0.log
*** Direct rendering support is highly experimental for Radeon 9500
(WW) RADEON(0): Direct rendering disabled

There are some way to enable DRI in my PowerBook?

Thanks in advance

Pietro