[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [RFC PATCH] set current_state to D0 in register_slot
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> --- diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index cb23aa2..e610cfe 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -212,6 +212,7 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv) pdev = pci_get_slot(pbus, PCI_DEVFN(device, function)); if (pdev) { + pdev->current_state = PCI_D0; slot->flags |= (SLOT_ENABLED | SLOT_POWEREDON); pci_dev_put(pdev); } _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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