Subject: Re: A2091 DMA driver
To: Peter Meyer <>
From: Eduardo E. Horvath <>
List: amiga-dev
Date: 01/26/1995 09:10:35
On Thu, 26 Jan 1995, Peter Meyer wrote:

> Hi !
> I have problems with the 2091 support in NetBSD1.0. I run NetBSD on an A2000
> with A2630 (4MB) and 12MB on the DKB A2632 expansion. The A2091 can't do DMA
> transfers in the A2632 memory, so i had to switch off A2091 DMA (is there
> another possibility ?).

In theory, the driver should be allocating bounce buffers from your Z2
(A2630) memory or CHIP RAM.  I don't think that this code has ever been
tested.  Compare the 2091 code with the A3000 code and the GVP code.  All are
based on the same SCSI controller and at least one of these should allocate
bounce buffers correctly. 

Another thing to look at is amiga_start.c and make sure that the memory 
mapping routines aren't getting confused by your high RAM and absence of 
Z3 bus.  This is where the bounce buffers should be assigned.