Messages in this thread | | | Date | Tue, 24 Oct 2006 16:36:32 -0600 | From | Matthew Wilcox <> | Subject | Re: Ordering between PCI config space writes and MMIO reads? |
| |
On Tue, Oct 24, 2006 at 02:51:30PM -0700, Roland Dreier wrote: > > I think the right way to fix this is to ensure mmio write ordering in > > the pci_write_config_*() implementations. Like this. > > I'm happy to fix this in the PCI core and not force drivers to worry > about this. > > John, can you confirm that this patch fixes the issue for you?
Hang on. I wasn't thinking clearly. mmiowb() only ensures the write has got as far as the shub. There's no way to fix this in the pci core -- any PCI-PCI bridge can reorder the two.
This is only really a problem for setup (when we program the BARs), so it seems silly to enforce an ordering at any other time. Reluctantly, I must disagree with Jeff -- drivers need to fix this. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |