BUG: invalid MAX_DMA_ADDRESS macro for i386?

[Paul]

	Dear All;

	2.4.6-ac5 kernel, i486.
	Well, I have tracked down my problem. We see a comparison
like this to  determine whether to use a bounce buffer:

if ( virt_to_bus(addr+buflen) >= MAX_DMA_ADDRESS) {
...(use a bounce buffer 'cause that addr is not dma-able)...

	This is not working, because MAX_DMA_ADDRESS is defined
so:

./include/asm-i386/dma.h:
#define MAX_DMA_ADDRESS (PAGE_OFFSET+0x1000000)

	This looks to come out to 0xc1000000. This does not seem
to be comparable to a bus address. eg. 0x100000 == 16M, the DMA
limit on ISA bus.
	This driver doesnt work on ISA machine with > 16M, as the
bounce buffer never gets used. (forcing its unconditional use
makes it work fine)
	So, what is wrong here? Macro, or conditional? Clue me in
so I can fix it correctly.

Paul
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