diff options
Diffstat (limited to 'drivers/pci/pci-acpi.c')
| -rw-r--r-- | drivers/pci/pci-acpi.c | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index f94c86fbc669..8eb599708de8 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -1,6 +1,6 @@ /* * File: pci-acpi.c - * Purpose: Provide PCI support in ACPI + * Purpose: Provde PCI support in ACPI * * Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com> * Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com> @@ -17,6 +17,7 @@ #include <acpi/acpi_bus.h> #include <linux/pci-acpi.h> +#include "pci.h" static u32 ctrlset_buf[3] = {0, 0, 0}; static u32 global_ctrlsets = 0; @@ -209,6 +210,49 @@ acpi_status pci_osc_control_set(u32 flags) } EXPORT_SYMBOL(pci_osc_control_set); +/* + * _SxD returns the D-state with the highest power + * (lowest D-state number) supported in the S-state "x". + * + * If the devices does not have a _PRW + * (Power Resources for Wake) supporting system wakeup from "x" + * then the OS is free to choose a lower power (higher number + * D-state) than the return value from _SxD. + * + * But if _PRW is enabled at S-state "x", the OS + * must not choose a power lower than _SxD -- + * unless the device has an _SxW method specifying + * the lowest power (highest D-state number) the device + * may enter while still able to wake the system. + * + * ie. depending on global OS policy: + * + * if (_PRW at S-state x) + * choose from highest power _SxD to lowest power _SxW + * else // no _PRW at S-state x + * choose highest power _SxD or any lower power + * + * currently we simply return _SxD, if present. + */ + +static int acpi_pci_choose_state(struct pci_dev *pdev, pm_message_t state) +{ + char dstate_str[] = "_S0D"; + acpi_status status; + unsigned long val; + struct device *dev = &pdev->dev; + + /* Fixme: the check is wrong after pm_message_t is a struct */ + if ((state >= PM_SUSPEND_MAX) || !DEVICE_ACPI_HANDLE(dev)) + return -EINVAL; + dstate_str[2] += state; /* _S1D, _S2D, _S3D, _S4D */ + status = acpi_evaluate_integer(DEVICE_ACPI_HANDLE(dev), dstate_str, + NULL, &val); + if (ACPI_SUCCESS(status)) + return val; + return -ENODEV; +} + /* ACPI bus type */ static int pci_acpi_find_device(struct device *dev, acpi_handle *handle) { @@ -255,6 +299,7 @@ static int __init pci_acpi_init(void) ret = register_acpi_bus_type(&pci_acpi_bus); if (ret) return 0; + platform_pci_choose_state = acpi_pci_choose_state; return 0; } arch_initcall(pci_acpi_init); |