Alex Chiang wrote: > * Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>: >> Kenji Kaneshige wrote: >>> Alex Chiang wrote: >>>> Hi Kenji-san, >>>> >>>> * Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>: >>>>> There had been reported a problem that pciehp driver mis-detect the >>>>> non hot-pluggable slot as hot-pluggable on some platforms. The cause >>>>> of this problem is hot-plug capable bit in Slot Capabilities register >>>>> is set improperly by BIOS or hardware. It seems BIOS/hardware problem, >>>>> but I think pciehp driver needs workaround for this problem. >>>> Do you know the magnitude of how many machines have broekn BIOS? >>>> >>>> I see from your patch 2/2 that there is a strong correlation >>>> between duplicate slot names and incorrect hot-plug capable bit. >>>> If that's true, then I guess there are a lot of broken machines >>>> out there... >>>> >>>> http://www.kerneloops.org/searchweek.php?search=pci_create_slot >>>> >>>> I was just wondering if we could quirk this somehow, but if you >>>> think there are too many broken machines out there, then your >>>> approach seems pretty reasonable. >>>> >>> Please note that pciehp and ACPI PCI slot detection driver have >>> different naming method. The pciehp driver uses Physical Slot Number >>> bit in Slot Capabilities register for slot naming. On the other hand, >>> ACPI PCI slot detection driver uses ACPI _SUN method for slot naming. >>> So, pciehp's duplicate slot name problem is different from the problem >>> reported in the above URL, I think. >>> >> Maybe I was wrong. >> Is the cause that pciehp driver registered a slot with a wrong name >> before ACPI PCI slot detection driver tried to register slots? > > No, I think you were right. My guess is that those warnings came > from a broken ACPI namespace. > Oh, that's bad news also for my patches, because my patch has an assumption that PCI hotplug slots are properly defined in ACPI Namespace even if hotplug capable bit is wrongly set in the slot capabilities register. For those machines, maybe we need quirk approach one by one, I think. By the way, do you have DSDT dump image of those broken ACPI Namespace? I would like to look, if possible. > In that case, I still wonder how many machines have broken native > PCIe hotplug that have the wrong bit set in the capabilities > register (and also falsely advertise hotplug). > > Do you know? I don't know the actual number. But the reported machines on the ML were popular laptop, so I think the number is relatively large. In addition, I got a x86 server recently and it has this problem (This is why I can make patches this time. I had been looking for the reproduction environment, and I finally got it). Thanks, Kenji Kaneshige -- 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
