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Re: pci_mapreg_map(9) and prefetchable BARs
On Tue, Aug 09, 2011 at 05:38:43PM -0400, Michael wrote:
> Why would it fail if the BAR is marked as prefetchable but someone
> requests a non-prefetchable mapping? The bit is just a hint.
My phrasing was probably awkward. It wouldn't fail in that case.
Here's the proposal:
1 Safety first: pci_mapreg_map() should map every BAR as
if it is non-prefetchable (i.e., non-cached, non-write
combining, order enforced) unless the caller passes the hint
2 pci_mapreg_map() should turn on caching, write-combining, et cetera,
on a prefetchable BAR if the caller passes BUS_SPACE_MAP_PREFETCHABLE.
3 pci_mapreg_map() should return 1 (indicating an error) before it
David Young OJC Technologies
dyoung%ojctech.com@localhost Urbana, IL * (217) 344-0444 x24
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