On Sat, Sep 01, 2007 at 12:11:52PM +0200, Andi Kleen wrote: > On Thursday 30 August 2007 19:43:14 Robert Richter wrote: > > This patch implements PCI extended configuration space access for > > AMD's Barcelona CPUs. It extends the method using CF8/CFC IO > > addresses. An x86 capability bit has been introduced that is set for > > CPUs supporting PCI extended config space accesses. > > We shouldn't need this because extended config space should work > here and Linux should use it > (especially after we added the ugly Barcelona workaround into that code)
This patch is needed for all buggy BIOSes that don't correctly set up MCFG. > The only exception would be if the user disables MMCONFIG in CONFIG, but > that's > their own fault then. No, as you stated yourself there are two exceptions. And the more serious one is the BIOS issue. > Ok there might be buggy BIOS around with no or no usable MCFG table, but since > extended config space is not really a critical feature that's not a big issue. Not sure why you assume extended config space (ECS) is not critical. Ok, for a lot of stuff it does not matter. But it is needed for some devices for full functionality. E.g. for perfmon (family 0x10/extended inerrupts) extended config space access is a prerequisite. > So I don't think we want this special case code at all and should > just rely on MMCONFIG. Rely on something unreliable (due to buggy/incomplete BIOS)? I don't think we should do this. IMHO it is best to try to use MMCONFIG if it's working and to use a fallback (e.g. CF8 ECS access for family 0x10) if available. Regards, Andreas -- Operating | AMD Saxony Limited Liability Company & Co. KG, System | Wilschdorfer Landstr. 101, 01109 Dresden, Germany Research | Register Court Dresden: HRA 4896, General Partner authorized Center | to represent: AMD Saxony LLC (Wilmington, Delaware, US) (OSRC) | General Manager of AMD Saxony LLC: Dr. Hans-R. Deppe, Thomas McCoy - 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/
