On Tue, Dec 01, 2009 at 12:40:03PM -0800, Yinghai Lu wrote: ... > > I assumed Yinghai's objection was based on a specific problem he had > > seen with writing upper32 register. Bjorn asked the right question. > > If there isn't a specific problem, I'd prefer AW's simpler patch. > > we just should not touch that register if the HW only support 32bit pref mmio. Why not? I agree the PCI-PCI spec defines how to determine if a PCI Bridge supports 64-bit Pref MMIO (using upper32 - or not). But spec also doesn't prohibit writing to a read-only register. Writing this Read-Only register so far hasn't caused any problems. > > I'm also thinking the resource allocation design which uses resource > > flags to indicate resources assigned (e.g a resource is 32-bit) rather > > than HW attributes is broken. We should be able to allocate 32-bit Option > > ROM into a 64-bit prefetchable MMIO window that is programmed with upper32 > > as zeros without changing the resource type. The resource allocation > > code only be looking at Resource "Type" when (re)programming > > window registers. The rest of the time (programming BARs) should be > > able to just test "if it fits". > > IORESOURCE_MEM_64 is the flags that the resource could be assigned to >4g range. > so it is NOT assigned resource ... *shrug* I don't have time to work on the broader issue. thanks, grant -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
