ISA DMA

[Adrian Cox]

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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