On Mon, 28 Feb 2011 16:20:11 +0000 Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> wrote: > Hi all, > if a device doesn't support power management (pm_cap == 0) but it is > acpi_pci_power_manageable() because there is a _PS0 method declared for > it and _EJ0 is also declared for the slot then nobody is going to set > current_state = PCI_D0 for this device. This is what I think it is > happening: > > > pci_enable_device > | > __pci_enable_device_flags > /* here we do not set current_state because !pm_cap */ > | > do_pci_enable_device > | > pci_set_power_state > | > __pci_start_power_transition > | > pci_platform_power_transition > /* platform_pci_power_manageable() calls acpi_pci_power_manageable that > * returns true */ > | > platform_pci_set_power_state > /* acpi_pci_set_power_state gets called and does nothing because the > * acpi device has _EJ0, see the comment "If the ACPI device has _EJ0, > * ignore the device" */ > > > at this point if we refer to the commit message that introduced the > comment above (10b3dcae0f275e2546e55303d64ddbb58cec7599), it is up to > the hotplug driver to set the state to D0. > However AFAICT the pci hotplug driver never does, in fact > drivers/pci/hotplug/acpiphp_glue.c:register_slot sets the slot flags to > (SLOT_ENABLED | SLOT_POWEREDON) but it does not set the pci device > current state to PCI_D0. > > So my proposed fix is also to set current_state = PCI_D0 in > register_slot. > Comments are very welcome. > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> Yeah, looks fine. ACPIPHP is happy for the attention. :) -- Jesse Barnes, Intel Open Source Technology Center -- 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
