Subject: Re: Problem reports?
To: None <,>
From: Olaf Seibert <>
List: amiga-dev
Date: 08/30/1994 00:56:42
Chris Hopps wrote:
> Regarding the A2091 in a A4000 problems.  Is anyone out there
> using an A2091 in a A2000?  If so are you seeing problems?

The problem with 2091s in 4000s under AmigOS is two things:
the driver is run from the ROM on the card and that ROM is not
cached, and many times it gets to do polled I/O because it cannot
do DMA outside th eZ2 address space.

DMA to chip mem should normally work okay, and marking the ROM
as cachable together increase the speed considerably (but still
not as fast as on a 2000).

I have however read about other people having problems with DMA
from a 2091 to their 4000's chip memory. It might be a problem
that happens in more 4000s than just mine. (As I noted before,
a 2091 in my 4000 hangs badly, but the same 2091 works perfectly
in my 2000).

___ Olaf 'Rhialto' Seibert     Ooey-Gooey-Fluffy-Barfie
\X/ I'm not weird, I'm differently percepted. D787B44DFC896063 4CBB95A5BD1DAA96