Messages in this thread | | | Date | Wed, 2 Jan 2002 10:31:14 +0100 | From | Jens Axboe <> | Subject | Re: [linux-usb-devel] Re: highmem and usb [was: "sr: unaligned transfer" in 2.5.2-pre1] |
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On Tue, Jan 01 2002, David Brownell wrote: > > > No, you can always ask to get pages low mem bounced. Highmem is no > > > requirement, and if your device really can't support it there's no point > > > in attempting to support it. > > > > I presume there is some overhead in bouncing to lowmem? I imagine that > > highmem support for the HCDs wouldn't be that difficult -- they are just > > PCI devices, after all. > > I'm unclear on what "bouncing to lowmem" involves, but I'd rather avoid > teaching all three HCDs a second model for addressing transfer buffers. > > At least until later in the 2.5 series, when we believe they'll share a lot > more common code and so that new model can be taught to just ONE > piece of code. Fixing bugs in one place easier than in three!
Ehm I was discussing 2.5, 2.4 will always bounce the high mem pages for you so it's moot there.
-- Jens Axboe
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