Subject: Re: g4, cache and speculative addressing
To: Michael <macallan18@earthlink.net>
From: Riccardo Mottola <rollei@tiscalinet.it>
List: port-macppc
Date: 06/27/2005 19:51:36
Hey,

I have some news. I contacted the riginal owner of the card and I got a
small installation manual (useless, no tech daya) and the original
GaugePro utility and the card control panel.


> 
> I wouldn't worry about +/- 1MHz in the probed CPU clock, but what you
> said earlier - 44MHz bus clock - doesn't make much sense at all. Either
> the card is running bus and core asynchronously ( seems odd ), at a very
> odd ratio ( seems even weirder ) or the software got something wrong.
> I'd suspect the bus runs slightly over 50MHz and the core runs at 8x bus
> clock.

I can ease things now; the official utility says the bus is running at
44.5 mhz with a  multiplier set to 9.0. THus it is 400.5 mhz and so
other utilities may report 401...


> > could that be useful? From what you say I gather it would be stupid,
> > since I have to set up the correct type of cache.
> 
> Does your utility say anything about cache RAM type? It's probably not
> pipelined burst.

the official utility says it is backside cache. I can select write
though or write back and write back is the default, it is also the
recommended and marked as "faster". So we should stick to that :)

now I start the other utility (after installing its extension to avoid
conflicts) and it says It is a pipelined synchronous 0.5ns cache, PB2

> > > Most definitely and yes I think so. It would at least tell us what
> > > MacOS uses.
> >
> > 0xB9080000
> >
> > I wonder to what netbsd sets them with my settings...
> 
> Let's see...
> #define   L2CR_L2E                0x80000000 /* 0: L2 enable */
> #define    L2SIZ_1M               0x30000000
> #define    L2CLK_20               0x08000000 /*            / 2   */
> #define    L2RAM_PIPELINE_BURST   0x01000000
> #define   L2CR_L2WT               0x00080000 /* 12: L2 write-through. */
> 
> So pipeline burst is what MacOS uses too, but you may want to add
> L2CR_L2WT.
> 
> >       - it seem a tad more stable, but the ssytem freezed after a cvs
> > update, a bit of compile and X usage.
> 
> Maybe putting the cache into write-through mode helps.


now, with the official utility is is set write-back and indeed the other
utility reports me a

0xB9000000 string.

I will stress the system under macos now, but I don't expect problems,
If they areise I'll tell you all. Just to be sure it isn't my cache
going crazy. To be precise I also reenabled the (useless) L3 cache,
supposing netbsd doesn't disable it..

but I really start to fear Netbsd is going wrong. ANd since other people
report so many problems with G4...

some of these people aving problems use "official" G4s or are they all
upgrades?

-R