On Sun, 2 Feb 1997, Markus Baeurle wrote:

> When was DMA for the Cumana and Powertec drivers tested last?  I mean
> several changes were made recently, especially the bugfix to the
> interrupt system, so couldn't it be that DMA is working now but nobody
> has noticed yet?  I'd like to test it (especially as I'm currently
> making a fresh backup of my harddisk, both RISC OS and RiscBSD so I
> could even cope with my harddisk getting corrupted) but this means
> somebody from the kernel team would have to compile a kernel with DMA
> for the Cumana driver enabled. 
Ok DMA will not be working as DMA support is not inplace in the existing
drivers. This was due to the fact that the interrupt problem needed to be
fixed before DMA could be implemented.
However now that interrupts are fixed Scott and myself have been doing a
bit of playing with DMA on the Cumana and Powertec cards.
The major problem we have had to sort out is the fact that the IOMD DMA
information in the TRM is not actually correct and DMA in practice behaves
slightly differently. This is taken some time to suss out.
The current sticking point in in the generic sfas code. I need to add
support for cache cleaning and syncing for DMA transfers.

DMA is getting very close ....

Cheers,
				Mark