I also was able to manually apply the patch to my 2.4.21-rc1 kernel...
Athough I have a geforce2 ti I wanted to try this new patch and it works perfectly! There were no problems at all and I use the nvidia binary driver. Checked /proc/drivers/agp/status and it sais "AGPGART"
I really wonder why nvidia doesn't release this patch to the public... IT IS GREAT
So if you have a Radeon and cannot use it until now... GET THIS PATCH!!!