I have two questions related to MIPS which someone may be able to help
with. Sorry for the long post.
Firstly I don't know if you've heard about the upgrading of the RM5200
300MHz CPU modules in SGI O2's with RM7000C 600MHz chips.
You can read about it at www.nekochan.net.
My question is about the possibility of someone helping out with
modifying the O2's PROM to recognise the RM7900 CPU from PMC-Sierra.
Currently the RM7000C running at 600Mhz is a working modification. The
RM7900 runs at up to 900Mhz and would breathe new life into the little O2's.
Details from a post on nekochan.net as to what needs to be done:
This guy was the one who has pioneered all of the CPU upgrades currently
going on with SGI machines.
"For the O2, when you start the computer the CPU board reads the data
from the boot-mode PROM chip (the Xilinx chip) into specific registers
on the CPU chip and does a Power On Self Test (POST). If the POST
passes, the ip32PROM then reads that data from the specific CPU chip
registers and checks that the CPU module is returning data values the
ip32PROM recognizes and passes those data values on to IRIX for the
system. The problem is that the data is in different registers and has
different values for the RM7900 series of chips than the RM7000 series
of chips. The RM7000 chips and the RM5270 chips use the same data
registers so the ip32PROM sees the RM7000 chips just fine, not so with
the RM7900 chips. When ip32PROM does not see a data value it recognizes
(for whatever reason), it halts the system at that point.
So at least three things need to be done to get this project back on track:
1.) a way needs to be found to tell the ip32PROM the correct registers
to look in for the data on the RM7900 CPU chip
2.) new values need to be added to the ip32PROM's list of possibe data
values for a couple of items
3.) the setup for the L2 cache in the ip32PROM needs to be changed as
the RM7900 chips start the cache memory at a different memory location
than the RM7000 chips
If there is someone out there who understands the ip32PROM and how to
modify the bin file, I will help them any way I can but the software
part of this is beyond my understanding."
If anyone can help out with this, or know someone who can help, it would
be much apreciated.
Not having played with Linux on my O2, I don't know the details, but are
you able to run dual monitors with a second video card in the PCI slot?
If so does anyone think it would be possible to port a video card driver
to Irix to be able run a second screen. Unfortunately the dualhead
monitor adaptor isn't really an option as they are very difficult to
find and expensive.