In article <2096.195.153.38.125.1034187701.squirrel@paradox.demon.co.uk>
chris@dokein.co.uk wrote:

> > A bit off topic, but does ISA DMA work on these ports?
> > Last time I tried AHA-1542 and PCnet-ISA on cats,
> > both of them didn't work at all.
> 
> No idea, I've not tried ISA cards in my cats, I plan to at some point
> soon, but first I suspect that the mess that is isa with footbridge needs
> tidying up.  It doesn't surprise me if they didn't work, currently isa
> interrupts happen at IPL_BIO on the footbridge, so if we go to splbio or
> higher no isa interrupts will get through, this means that any other
> footbridge interrupts can block the isa ones very easily.

Hmm, that's the reason why I got messages "com0: xx silo overflow"
from com and "ne0: warning - receiver ring buffer overrun" from ne2000.
It's great if they are fixed.

> > Current _isa_bus_dmamap_load() in footbridge/isa/isadma_machdep.c
> > returns physical address for ds_addr, but is it really OK for 24bit ISA
> > bus? And does cats really require bounce-buffer for isadma?
> 
> No idea, I believe it'll need the standard pc method of bounce buffers, as
> it's a standard PC ali southbridge.

So maybe the south bridge requires bounce buffer, but I doubt
the physical address of main memory starts from 0x0.
---
Izumi Tsutsui
tsutsui@ceres.dti.ne.jp