Subject: A2091 DMA driver
To: None <amiga-dev@NetBSD.ORG>
From: Peter Meyer <>
List: amiga-dev
Date: 01/26/1995 12:36:49
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 ?).

My suggestion: It should be possible to use both memory segments and the
driver has to test if DMA is possible for the transfer. The DMA Mask is
already set, but it seems to have no effect... Perhaps a better solution would
be to allocate a buffer in the memory of the A2630 where controller can DMA to,
make DMA transfers to the buffer and copy the buffer to the non DMA ram.

Is there anybody who works on the A2091 driver at the moment or can someone
tell me what is planned on this subject and what is possible or not ?

At the moment, disk acces with the A2091 with DMA switched off is terribly
slow :-((