Subject: Re: plan to merge cats and netwinder isa_machdep.c
To: None <Richard.Earnshaw@arm.com>
From: Izumi Tsutsui <email@example.com>
Date: 10/11/2002 01:08:31
In article <200210101507.g9AF7wD15075@pc960.cambridge.arm.com>
> True, but the other issue (24-bit address space) would mean that I'd
> expect on average for 7/8ths of the buffers to be outside the addressable
> range (I've got 128 Mb of ram). Yet the failures, though there are far
> less common than that.
"Out of addressable range" would be handled by bounce buffer,
and the real problem is whether the DMA address for bus-master devices
is physical address (like on i386) or not.
I guess only isadma by 8237 DMA controllers works
(higher address may be handled by the chipset?),
but all bus-master devices on ISA would have trouble.