[CentOS] DMA disabled on SATA disk with Core Duo/i955 machine (Inspiron 6400)

I am trying to use CentOS 4 on this machine and it does not allow me to
set DMA to 1, it just says that it is not possible. I have tried
updating to the latest release and it still won't work.

I have searched for it on Google and there is a thread mentioning the
same machine and CentOS, but none of the solutions (-p, -X 12) seem to
work at all and there is no "it works!!!!!" message.

Is there anyway I can get DMA working or will I have to wait for CentOS
5? Will any of the "unsupported" kernels work? (I would try Ubuntu's
kernel on CentOS, as I am successfuly using that distribution, but it
is a bit stupid not to use SELinux and it probably wouldn't work
either).

Thanks

Gabriel

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