On Wed, 5 Oct 2011, Ajaykumar Hotchandani wrote: > During test of one IB card with guest VM, found that, msi is not initialized properly. > > It turns out __write_msi_msg will do nothing if device current_state is not PCI_D0. > And, that pci device does not have pm_cap in guest VM. > > There is an error in setting of power state to PCI_D0 in pci_enable_device(), but error is not returned for this. > Following is code flow: > pci_enable_device() --> __pci_enable_device_flags() --> do_pci_enable_device() --> pci_set_power_state() --> __pci_start_power_transition() > We have following condition inside __pci_start_power_transition(): > if (platform_pci_power_manageable(dev)) { > error = platform_pci_set_power_state(dev, state); > if (!error) > pci_update_current_state(dev, state); > } else { > error = -ENODEV; > /* Fall back to PCI_D0 if native PM is not supported */ > if (!dev->pm_cap) > dev->current_state = PCI_D0; > } > > Here, from platform_pci_set_power_state(), acpi_pci_set_power_state() is getting called and that is failing with ENODEV because of following condition: > if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0",&tmp))) > return -ENODEV; > > Because of that, pci_update_current_state() is not getting called. > > With this patch, if device power state can not be set via platform_pci_set_power_state and that device does not have native pm support, then PCI device power state will be set to PCI_D0. > > Signed-off-by: Ajaykumar Hotchandani<ajaykumar.hotchandani@xxxxxxxxxx> > Signed-off-by: Yinghai Lu<yinghai.lu@xxxxxxxxxx> 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 -- 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