Messages in this thread | | | Date | Tue, 24 Oct 2006 15:22:10 -0400 | From | Jeff Garzik <> | Subject | Re: Ordering between PCI config space writes and MMIO reads? |
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On Tue, Oct 24, 2006 at 12:13:19PM -0700, Roland Dreier wrote: > 1) Is this something that should be fixed in the driver? The PCI > spec allows MMIO cycles to start before an earlier config cycle > completed, but do we want to expose this fact to drivers? Would > it be better for ia64 to use some sort of barrier to make sure > pci_write_config_xxx() is strongly ordered with MMIO?
The PCI config APIs have traditionally enforced very strong ordering. Heck, the PCI config APIs often take a spinlock on each read or write; so they are definitely not intended to be as fast as MMIO.
Jeff
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