On Mon, 12 Oct 2009 22:34:53 +0200 Ingo Molnar <mingo@xxxxxxx> wrote: > > * Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote: > > > On Tuesday 06 October 2009 11:51:22 am Yinghai Lu wrote: > > > Bjorn Helgaas wrote: > > > > On Sunday 04 October 2009 10:54:24 pm Yinghai Lu wrote: > > > >> for intel system with multi IOH. we could read peer root > > > >> resource from PCI conf, and don't trust _CRS again for root bus > > > > > > > > Ugh. Are we going to end up with amd_bus.c, intel_bus.c, > > > > nvidia_bus.c, broadcom_bus.c, serverworks_bus.c, etc.? > > > only needed when you have muti ... > > > > I think that translates to "yes, we will need all those bits as > > soon as those vendors support larger systems with multiple IOHs." > > And I think that's the wrong answer. > > Why is having cleanly separated per vendor information/driver wrong? > I think it's the right answer in most cases. _Especially_ when the > other option is to 'rely on the firmware'. > > > > again we should trust HW conf than BIOS. > > > > Certainly there's a tradeoff between a generic driver that relies > > on the BIOS, and a platform-specific driver that uses only the > > hardware. The first leaves us vulnerable to BIOS bugs, but the > > second leads to a plethora of drivers that require updates as > > hardware changes. > > We do that quite well in Linux - it's one of our main strengths. > > Why should we have to rely on correct firmware? Why is it wrong to > know about the hw's structure, to query the hardware and ignore the > firmware if the hardware state tells us otherwise? Right, I think the approaches are complimentary. We want the hw info, for cases where the fw is broken or there's no support for a given configuration, but we also want the fw info for cases where we don't yet have hw info (e.g. the bridge driver isn't updated) or it isn't complete. -- Jesse Barnes, Intel Open Source Technology Center -- 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
