Re: CONFIG_BIGMEM and rawio

Manfred Spraul (manfreds@colorfullife.com)
Fri, 03 Sep 1999 10:13:37 +0200

"Stephen C. Tweedie" wrote:
> Hi,
> There are PCI controllers which ignore the high bit of the address
> line. Their limit is 2GB. Above that they need bounce buffers. Sad
> but true.

2 GB memory cost > $7000 (4* 512 Mb ECC memory)

I think everyone who needs > 2 GB memory _and_ raw-io will buy a new
controller instead of relying on bounce buffers, so I would not add them
unless
* the required code is really short [shorter than the 70 lines needed
for swap]
* zero overhead for the normal case.

--
	Manfred


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