SGI O2 Prom modification

[Glenn Barry]

Hi There,

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:

http://forums.nekochan.net/viewtopic.php?t=3314

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.

Secondly.

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.

Thanks

Glenn

[Kumba]

Post by Glenn Barry
Hi There,
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.

AFAIK, this ability isn't too supported anymore. The guy doing this has
apparently decided to quit. While I'm sure this doesn't make such
modifications impossible, it likely makes them more difficult and more expensive.

RM7000 has issues in Linux anyways. L3 cache is disabled (atleast on the
official SGI RM7000. Not sure if the 600MHz R7000 has an L3 cache as well),
and the scsi system isn't working in this system yet. There's possibly
others, but so few people have access to these kinds of machines that it makes
testing diffcult.

Post by Glenn Barry
My question is about the possibility of someone helping out with
modifying the O2's PROM to recognise the RM7900 CPU from PMC-Sierra.

This would quite likely require direct access to the source code of the IP32
PROM. I think only IRIX developers have this access, and there are likely
license issues that would get in the way of modifying such code to allow for
detection of the RM7900

Modifying the binary is most assuredly way more difficult than gaining access
to ip32PROM source and modifying it directly (and solving license issues).
The level of change to the binary needed to make the ip32PROM detect a new CPU
would require extremely detailed knowledge of the binary format the ip32PROM
is in, SGI O2 systems, and how the PROM even functions. I'd wager a guess
that a super-skilled SGI engineer might possibly pull this off, given enough
caffeine.

Post by Glenn Barry
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?

Very unlikely in the current state, most video cards require initialization
from an x86 bios to function. There are ways around that, but then there's
the problem of the O2 PCI slot not operating at 100%.

Post by Glenn Barry
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.

About the only guy who can pull something like that off currently is Stan, the
guy who did the Octane port, since he reverse-engineered the Impact card on
Octanes. Short of that, not without documentation, and alot of time. And
you'll need more weight than that in the core of a neutron star to get SGI to
dig up those docs (since they're probably lost in a black hole anyways).


--Kumba

[Glenn Barry]

Hi Kumba,

read below

Post by Kumba

Post by Glenn Barry
Hi There,
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.

AFAIK, this ability isn't too supported anymore. The guy doing this
has apparently decided to quit. While I'm sure this doesn't make such
modifications impossible, it likely makes them more difficult and more expensive.

This modification is currently being done with RM5200 boards and
replacing the CPU. You can read more about it at
http://forums.nekochan.net/viewtopic.php?t=1071

The RM7000C @ 600MHx chip currently works fine in IRIX, sorry I should
have specified that this isn't specifically related to Linux, I just
thought that you people would have the best knnowledge of the SGI's
outside SGI themselves, given that you've been able to port Linux to
some of their machines.

Post by Kumba
RM7000 has issues in Linux anyways. L3 cache is disabled (atleast on
the official SGI RM7000. Not sure if the 600MHz R7000 has an L3 cache
as well), and the scsi system isn't working in this system yet.
There's possibly others, but so few people have access to these kinds
of machines that it makes testing diffcult.

Post by Glenn Barry
My question is about the possibility of someone helping out with
modifying the O2's PROM to recognise the RM7900 CPU from PMC-Sierra.

This would quite likely require direct access to the source code of
the IP32 PROM. I think only IRIX developers have this access, and
there are likely license issues that would get in the way of modifying
such code to allow for detection of the RM7900

Hmmm...given that the O2 line is discontinued I wonder if SGI would
really object to having the code modified.

Post by Kumba
Modifying the binary is most assuredly way more difficult than gaining
access to ip32PROM source and modifying it directly (and solving
license issues). The level of change to the binary needed to make the
ip32PROM detect a new CPU would require extremely detailed knowledge
of the binary format the ip32PROM is in, SGI O2 systems, and how the
PROM even functions. I'd wager a guess that a super-skilled SGI
engineer might possibly pull this off, given enough caffeine.

Yes that is where know how is in shortage, Chicage Joe got the hardware
side of things sorted for the upgrade to the RM70000C @ 600MHz and there
was no issue with the PROM as the CPU specs were identical to the RM5200

Post by Kumba

Post by Glenn Barry
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?

Very unlikely in the current state, most video cards require
initialization from an x86 bios to function. There are ways around
that, but then there's the problem of the O2 PCI slot not operating at
100%.

There is a secondary video card available for the O2's (apparently) but
with very low specs 8MB ram and something like a $2000 price tag.

So I was wondering if using an available XFree driver and possibly
either running a second X server or proting the Xfree driver to XSGI.

Post by Kumba

Post by Glenn Barry
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.

About the only guy who can pull something like that off currently is
Stan, the guy who did the Octane port, since he reverse-engineered the
Impact card on Octanes. Short of that, not without documentation, and
alot of time. And you'll need more weight than that in the core of a
neutron star to get SGI to dig up those docs (since they're probably
lost in a black hole anyways).

This sounds familiar, it;'s a shame SGI doesn't give more
help/documentation to people working with thier older machines, though I
can understand it not being financially feasible.

Glenn

Post by Kumba
--Kumba

[Robin H. Johnson]

Post by Glenn Barry

Post by Kumba
AFAIK, this ability isn't too supported anymore. The guy doing this
has apparently decided to quit. While I'm sure this doesn't make such
modifications impossible, it likely makes them more difficult and more expensive.

This modification is currently being done with RM5200 boards and
replacing the CPU. You can read more about it at
http://forums.nekochan.net/viewtopic.php?t=1071
have specified that this isn't specifically related to Linux, I just
thought that you people would have the best knnowledge of the SGI's
outside SGI themselves, given that you've been able to port Linux to
some of their machines.

Kumba and I do know all about the RM7000C work, as we are frequent
visitors to nekochan.

What Kumba was referring to what the mid-August post by ChicagoJoe (on
page 14) stating that the company that had been doing the BGA chip
replacement is not taking on any more work.

Post by Glenn Barry

Post by Kumba
This would quite likely require direct access to the source code of
the IP32 PROM. I think only IRIX developers have this access, and
there are likely license issues that would get in the way of modifying
such code to allow for detection of the RM7900

Hmmm...given that the O2 line is discontinued I wonder if SGI would
really object to having the code modified.

To get the PROM source, you'd really have to be in bed with SGI, as many
other folk from here have asked for a lot less and had no success.

[Glenn Barry]

Hi Robin,

O.K. I misunderstood when I thought that Kumba misunderstood. D'OH.

I think that our biggest hope is to find someone that maybe worked on
the O2 development, one of the engineers maybe, that would like to see
the O2 evolve to its ultimate potential. It might not involve getting
the source code if they did the mod for us, but knowing who in
particular to ask in the first place is the real challenge..

Glenn

Post by Robin H. Johnson

Post by Glenn Barry

Post by Kumba
AFAIK, this ability isn't too supported anymore. The guy doing this
has apparently decided to quit. While I'm sure this doesn't make such
modifications impossible, it likely makes them more difficult and more expensive.

This modification is currently being done with RM5200 boards and
replacing the CPU. You can read more about it at
http://forums.nekochan.net/viewtopic.php?t=1071
have specified that this isn't specifically related to Linux, I just
thought that you people would have the best knnowledge of the SGI's
outside SGI themselves, given that you've been able to port Linux to
some of their machines.

Kumba and I do know all about the RM7000C work, as we are frequent
visitors to nekochan.
What Kumba was referring to what the mid-August post by ChicagoJoe (on
page 14) stating that the company that had been doing the BGA chip
replacement is not taking on any more work.

Post by Glenn Barry

Post by Kumba
This would quite likely require direct access to the source code of
the IP32 PROM. I think only IRIX developers have this access, and
there are likely license issues that would get in the way of modifying
such code to allow for detection of the RM7900

Hmmm...given that the O2 line is discontinued I wonder if SGI would
really object to having the code modified.

To get the PROM source, you'd really have to be in bed with SGI, as many
other folk from here have asked for a lot less and had no success.

[Jan-Benedict Glaw]

Post by Kumba

Post by Glenn Barry
My question is about the possibility of someone helping out with
modifying the O2's PROM to recognise the RM7900 CPU from PMC-Sierra.

Modifying the binary is most assuredly way more difficult than gaining
access to ip32PROM source and modifying it directly (and solving license
issues). The level of change to the binary needed to make the ip32PROM

I'd not bet my a** on that. Modifying the binary firmware has got a
long, but rare, history. I remeber hacked PROM images for VAXen to
support larger SCSI disks. As long as you don't require a detailled CPU
detection, that should be possible. Hardcoding some values isn't all
thaaat hard. Making it correctly (preserving the formerly running
detection code for other CPUs) is a bit harder, of course :-)

MfG, JBG