Re: ISA DMA

David Müller (ELSOFT AG) wrote:

Seems like you are facing the same problem as i do. But IIRC i think you
have to adjust the code in include/asm/dma.h (and possibly other places)
as well (at least in 2.4.14, not sure about the later kernels).

The main problem I can see is that the code always writes to the
DMA_HI_PAGE_x registers, irrespective of whether they actually exist.
This should be harmless, as nothing else is mapped to those locations.

What south bridge do you use? Some of the newer ones offer 32bit
addressing capability for DMA.

Via686a. As I understand it, 32-bit DMA uses the DMA_HI_PAGE_x registers
from 0x487 to 0x48a, and the Via manual doesn't claim to have any
registers in that range. The only 32-bit DMA southbridge I've
encountered is the Winbond chip on the Sandpoint, and that chip doesn't
have UDMA66, USB, and audio.


--
Adrian Cox   http://www.humboldt.co.uk/


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