Re: lance patch, etc.

Thomas Bogendoerfer (tsbogend@bigbug.franken.de)
Wed, 17 Jan 1996 23:01:56 +0100 (MET)

> Hmmh, I don't understand how your patch can work. As far as I know,
> the Lance chip cannot generate any DMA address bigger than 16MB.

that's true for the ISA chips but not for the PCI and VLB chip.
Also when working in 16bit mode, the address for the init-block
is 32bit wide. The missing upper 8bit for the the other addresses
(descriptor rings, buffer addresses) are taken from that address.

> It seems to me that the proper solution would be to setup the second
> DMA window for the range 0..16MB and to make it identity mapped. No

I agree. This will also solve the "problem" with ISA busmasters,
which have no chance for supplying the missing upper 8bit. Probably
it's the only way, because I couldn't find anything about address
remapping in the SIO manual.

Thomas.