On Tue, 2013-07-09 at 15:56 +0800, Yijing Wang wrote: > Currently, pciehp_resume will call pciehp_enable_slot() to add > device if there is a device in the slot. But if the device was > present before suspend, it's no necessary to add again. Now in > such case, there is some uncomfortable message like > > pciehp 0000:00:1c.1:pcie04: Device 0000:03:00.0 already exists at 0000:03:00, cannot hot-add > pciehp 0000:00:1c.1:pcie04: Cannot add device at 0000:03:00 > > This problem was reported by Paul Bolle <pebolle@xxxxxxxxxx> > The discussion link: http://comments.gmane.org/gmane.linux.kernel.pci/19876 > > We can use PCIe Device Serial Number to identify the device if > device support DSN. > > currently: > 1. slot is empty before suspend, insert card during suspend. > In this case, is safe, pciehp will add device by check adapter > status register in pciehp_resume. > > 2. slot is non empty before suspend, remove card during suspend. > Also be safe, pciehp will remove device by check adapter > status register in pciehp_resume. > > 3. slot is non empty before suspend, remove card during suspend > and insert a new card. > Now pciehp just call pciehp_enable_slot() roughly. We should > remove the old card firstly, then add the new card. > > 4. slot is non empty before suspend, no action during suspend. > We should do nothing in pciehp_resume, but we call > pciehp_enable_slot(), so some uncomfortable messages show like above. > In this case, we can improve it a little by add a guard > if (!list_empty(bus->devices)). Great! I'm currently trying to bisect another problem, but hope to test this patch (and the preceding patch it apparently needs) in a few days. Please feel free to prod me if you think testing is needed but I'm taking to long to report back. Thanks! Paul Bolle -- 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
