To all ... Well, here is what I perceive we've got so far.
. Some PCI Northbridges do not work with MMCONFIG. . Some PCI BARs can overlap the MMCONFIG area during bus sizing. It is hoped that new BIOSes will locate MMCONFIG in an area safely out of the way of bus sizing code, but there can be no guarantees. . conf1 is going away in newer x86 implementations in the not too distant future. . The PCI express spec requires platforms to provide access to the extended config area, and there are express devices today using that area for AER. . There is no need to provide different PCI config access mechanisms at device granularity, since the PCI config access mechanism between the CPU and the Northbridge is opaque to the devices. PCI config mechanisms only need to differ at the Northbridge level. . We have a flurry of patches all claiming to solve all or some of these problems. Arjan, I realize it may not be possible for you to answer this question, but I feel compelled to ask it anyway. Is it possible that future x86 architectures will be implementing a SAL-like interface to abstract PCI config access altogether? Or can we condense these patches down to a set that does the following? . If the system is capable of conf1, then PCI config access at offsets < 256 should be confined to conf1. This solution is most effective for existing and legacy systems. . If the system does not support MMCONFIG, of if MMCONFIG is not working, then accesses to offsets > 256 return -1 and an error status. . For systems, where the conf1 mechanism is NOT available, then MMCONFIG should be the PCI access mechanism for all offsets. For such systems, we must assume that the BIOS has become smart enough to locate MMCONFIG in a region safe from encroachment by bus sizing code. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
