On Mon, Feb 12, 2001 at 05:46:22PM -0800, bob meader wrote:
> 
> 
> Mark Abene wrote:
> 
> > OK, so I enabled SYSCALL_DEBUG in netbsd-1.5R (I had to fix arch/mips/mips/
> 
> Sounds like a cache or dma problem (jazz buss).
> Did you try building with cache disabled?
> The second possibility could be verified by config a
> kernel to use a 'net card' plugged into the ISA/EISA
> slot... I have done that in the past to nfs boot
> from a 3com 3c503 .... just use a net card that
> doesn't require dma (most supported don't).

Unfortunately the only network cards I have are PCI.  What I still can't wrap
my brain around is the fact that with SYSCALL_DEBUG enabled, most of the
time I can actually get to a shell prompt in single-user mode (though the
first or second command I type will cause the hang).  And when these processes
hang, the Magnum will no longer be ping-able.  I just can't fathom why the
addition of some calls to scdebug_call and scdebug_ret would allow the boot
process to get so much further on.  I'm thinking along the lines of a memory
corruption problem (though it doesn't seem evident from my debug output),
or a possible dma problem causing the semi-random hangs, or even a TLB
problem, though I'm not really sure what the TLB map is SUPPOSED to look like
as compared to when I hang and do a "machine tlb" in DDB.
I'd be hesitant to think there was a L2 cache problem, as I've gone over that
code time and again in locore_mips3.S, and it's just too straightforward.
The only oddity along these lines is if I set L2CachePresent to "0", I get
a "TLB out of universe" panic right after autoconfig.

The whole thing is rather strange.  I just wish more people on the list who
have Magnums would TRY MY PATCHES so I have some feedback as to whether my
problems are a local event.

Cheers,
-Mark