On Mon, 10 Oct 2011, Ajaykumar Hotchandani wrote: > On 10/06/2011 09:47 PM, Stefano Stabellini wrote: > > On Thu, 6 Oct 2011, Yinghai Lu wrote: > >> On Thu, Oct 6, 2011 at 3:39 AM, Stefano Stabellini > >> <stefano.stabellini@xxxxxxxxxxxxx> wrote: > >>> I had the same issue and sent a patch a while ago to fix it, adding > >>> > >>> current_state = PCI_D0 in acpiphp_glue.c:register_slot > >>> > >>> it is strange that this does not work for you: > >>> > >>> http://marc.info/?l=linux-kernel&m=129891002722845&w=2 > >> So guest os has to load acpiphp instead of pciehp? > > > > maybe pciehp needs to make sure that current_state = D0 in > > pciehp_enable_slot, like acpiphp does > Here, acpi hotplugging is involved. > With your change in register_slot(), device will have proper power state when module is being loaded for the first time after booting. > However, while unload of pci module; following is in pci_device_remove(): > if (pci_dev->current_state == PCI_D0) > pci_dev->current_state = PCI_UNKNOWN; > > So, device power state state will remain PCI_UNKNOWN while module is loaded again. Subsequently, MSI write will do nothing. Does this mean that this bug would actually trigger even with devices that do support _EJ0 and power management? Because acpi_pci_set_power_state won't set current_state to PCI_D0 because the "hotplug driver will take care of _PSx" (see 10b3dcae0f275e2546e55303d64ddbb58cec7599) but the hotplug driver is not actually invoked when loading again a driver module of an existing pci device (the example you mention above)? -- 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
