Haven't checked this thread in a while been busy with other things
I figured some of this might be useful
when I first looked into this I figured I'd try and seperate out the kernel patches to 2.2.1 to isolate the sony related stuff then look at 2.4 afterwards
to give some clues to 2.6, but this kind of got put on hold once I figured out that the toolchain would need to be done first
2.4 is closer the mark but 2.2 seems to have more drivers supported for the hardware
below is some of the results I've got for seperating out the patches for 2.2.1
the original diff against the vanilla kernel was quite big, I've managed to get the unknowns down under 500K so far
some of this involved sifting through very old web pages for old versions of LVM / UDF
broken out patches dir
10-patch-mips-2.2.1.patch - 1.2Mb
CVS mips from
http://www.linux-mips.org/ "Sat Jun 12 18:39:27 1999 UTC"
11-patch-mips-2.2.1.patch - 95K
for some reason some of the version numbers in a lot of the mips files had been changed but the code was the same
20-patch-lvm-2.2.1.patch - 138K
LVM support added at some point
30-patch-udf-2.2.1.patch - 323K
UDF support
40-patch-usb-2.2.1.patch - 2.1Mb
some but not all of the USB stuff that they've added to the kernel
80-patch-ps2-obvious-2.2.1.patch - 844K
individual files that relate only to the PS2
90-patch-ps2-leftovercrap-2.2.1.patch - 464K
left over crap I've yet to sift through some R5900 related stuff (ps2)
also some bits of USB in there as well, plus anything else I've missed
applying the above to the 2.2.1 stock vanilla kernel should give you the same kernal as the stock for the PS2