why can't I make 2.6 kernels boot xfs?

[Christian Rice <xian@xxxxxxxxxxx>]

I've looked everywhere for a clue as to where I'm screwing up, but I've 
not figured this out.

For some reason, starting with 2.6.x, I can't get the kernels I build to 
mount the root partition.  It's kind of driving me batty, because I KNOW 
I have XFS and IDE support NAILED in the kernel, not as modules.

I get a VFS Panic every time along the lines of:

VFS: Cannot open root device hda3 or "hda3"
Please append a correct "root=" boot option

grub.conf:

title Red Hat Linux (2.6.3)
        root (hd0,0)
        kernel /vmlinuz-2.6.3 root=303 mem=nopentium idebus=66
        initrd /initrd-2.6.3.img



I've been building successful XFS kernels for a couple years, using them 
 on HUNDREDS of production workstations, servers and renderfarm 
machines.  This 2.6 business is confuscating.  Basically, I'm just 
downloading the kernel source from www.kernel.org, adding Tronds NFS_All 
patches, if any, and building the kernel with gcc 3.2.2.

No deja searches yield answers that help.  Everyone says "make sure 
you've turned on IDE support, blah blah.  It's on.

Any help yielding the bootable condition will earn my undying gratitude.

Thanks.