Quoting Garrett D'Amore <garrett_damore@tadpole.com>:

>> The real solution, I imagine, is to port i386's i8254 timecounter
>> support, as that is what IP12 uses.
>
> Well, if there is an i8254 in there, then yes, writing a tc framework
> for it would be very, very good.  I don't have hardware to test
> against.  Do you?  (I might be willing to do the work if you will test.)

None of my IP12 machines work anymore and they're all in another  
country at the moment anyhow. pooka@ or sekiya@ may be able to test,  
but we three are the only ones I know to have run the code at all. If  
you want to commit something that's just compile-tested, I won't  
disapprove. IP20 _might_ have an i8254 as well, but we have no use for  
it. If it does, someone may be able to test against it instead.

I'm not worried about IP12 having fantastic timekeeping, though. It's  
probably not worth your effort if it just runs as it used to. If you  
go about it anyhow, perhaps it would be important to keep in mind that  
SGI wired a 1MHZ master clock to TIMER2, which ticks the other two  
timers accordingly. At least, that's my recollection of a few years  
ago. There may be comments in the code, but I'm unsure.

> I can make test kernels for GENERIC_IP32, GENERIC_IP2x, and GENERIC_IP12
> available, if people want them to test with.

People on the list have been very helpful in trying out GENERIC_IP2x  
kernels. If you were to make one avaiable and put out a request,  
someone may oblige. I'm sure that if there were any introduced  
problems with the MIPS3 machines somebody will catch them before the  
next branch.

Thanks again for taking care of this.

Steve