[ACPI] PCI can now get suspend state from firmware
pci_choose_state() can now call
platform_pci_choose_state()
and ACPI can answer
http://bugzilla.kernel.org/show_bug.cgi?id=4277
Signed-off-by: David Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index f94c86f..8eb5997 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 @@
}
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 @@
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);