Messages in this thread | | | Date | Mon, 10 Oct 2011 17:32:09 +0530 | From | Ajaykumar Hotchandani <> | Subject | Re: [PATCH] PCI: Set device power state to PCI_D0 for device without native PM support |
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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@eu.citrix.com> 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.
Thanks, Ajay
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