Re: [PATCH 2/4] pcie: update slot power status only is power control is enabled

[Gerd Hoffmann]

  Hi,

>    pcie_cap_slot_post_load()
>        -> pcie_cap_update_power()
>            -> pcie_set_power_device()
>                -> pci_set_power()
>                    -> pci_update_mappings()

> Fix it by honoring PCI_EXP_SLTCAP_PCP and updating power status
> only if capability is enabled.

> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index d7d73a31e4..2339729a7c 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -383,10 +383,9 @@ static void pcie_cap_update_power(PCIDevice *hotplug_dev)
>  
>      if (sltcap & PCI_EXP_SLTCAP_PCP) {
>          power = (sltctl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_ON;
> +        pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> +                            pcie_set_power_device, &power);
>      }
> -
> -    pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> -                        pcie_set_power_device, &power);
>  }

The change makes sense, although I don't see how that changes qemu
behavior.

'power' defaults to true, so when SLTCAP_PCP is off it should never
ever try to power off the devices.  And pci_set_power() should figure
the state didn't change and instantly return without touching the
device.

take care,
  Gerd