Messages in this thread | | | Date | Thu, 19 Feb 2004 20:03:10 -0800 | Subject | Re: [PATCH] Intel x86-64 support merge | From | (David Mosberger-Tang) |
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>>>>> On Thu, 19 Feb 2004 17:06:58 -0500, Bill Davidsen <davidsen@tmr.com> said:
Bill> David Mosberger-Tang wrote: >>>>>>> On Thu, 19 Feb 2004 00:40:24 +0100, Arjan van de Ven >>>>>>> <arjan@fenrus.demon.nl> said: >> Arjan> On Wed, 2004-02-18 at 23:57, H. Peter Anvin wrote: >> >> Because they were caught by surprise and just hacked the chips >> >> they had in the pipeline, presumably.
Arjan> fair enough; I hope this means the next generation has this Arjan> wart fixed... >> I wouldn't hold my breath. My impression was that the Intel >> chipset folks don't want I/O MMU because (a) Windows doesn't need >> it and (b) real machines use (close-to-)64-bit-capable hardware.
Bill> Doesn't need it? Does that mean the Win64 uses bounce buffers Bill> for everything? Or am I totally misreading this?
Remember: I'm just the messenger here...
I have no idea what Win64 does, but obviously bounce buffering is only an issue for devices that can't address all physical memory. These days, even relatively low-end machines have devices that can address "more than enough" physical memory (I'm not sure exactly what the DMA limit of, say, a Kenai32 e1000 card is, but it's a lot more than 4GB).
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