PCI PM: Introduce __pci_[start|complete]_power_transition() (rev. 2)
The radeonfb driver needs to program the device's PMCSR directly due
to some quirky hardware it has to handle (see
http://bugzilla.kernel.org/show_bug.cgi?id=12846 for details) and
after doing that it needs to call the platform (usually ACPI) to
finish the power transition of the device. Currently it uses
pci_set_power_state() for this purpose, however making a specific
assumption about the internal behavior of this function, which has
changed recently so that this assumption is no longer satisfied.
For this reason, introduce __pci_complete_power_transition() that may
be called by the radeonfb driver to complete the power transition of
the device. For symmetry, introduce __pci_start_power_transition().
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 979ceb1..de54fd6 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -540,6 +540,53 @@
}
/**
+ * pci_platform_power_transition - Use platform to change device power state
+ * @dev: PCI device to handle.
+ * @state: State to put the device into.
+ */
+static int pci_platform_power_transition(struct pci_dev *dev, pci_power_t state)
+{
+ int error;
+
+ if (platform_pci_power_manageable(dev)) {
+ error = platform_pci_set_power_state(dev, state);
+ if (!error)
+ pci_update_current_state(dev, state);
+ } else {
+ error = -ENODEV;
+ /* Fall back to PCI_D0 if native PM is not supported */
+ pci_update_current_state(dev, PCI_D0);
+ }
+
+ return error;
+}
+
+/**
+ * __pci_start_power_transition - Start power transition of a PCI device
+ * @dev: PCI device to handle.
+ * @state: State to put the device into.
+ */
+static void __pci_start_power_transition(struct pci_dev *dev, pci_power_t state)
+{
+ if (state == PCI_D0)
+ pci_platform_power_transition(dev, PCI_D0);
+}
+
+/**
+ * __pci_complete_power_transition - Complete power transition of a PCI device
+ * @dev: PCI device to handle.
+ * @state: State to put the device into.
+ *
+ * This function should not be called directly by device drivers.
+ */
+int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state)
+{
+ return state > PCI_D0 ?
+ pci_platform_power_transition(dev, state) : -EINVAL;
+}
+EXPORT_SYMBOL_GPL(__pci_complete_power_transition);
+
+/**
* pci_set_power_state - Set the power state of a PCI device
* @dev: PCI device to handle.
* @state: PCI power state (D0, D1, D2, D3hot) to put the device into.
@@ -575,16 +622,8 @@
if (dev->current_state == state)
return 0;
- if (state == PCI_D0) {
- /*
- * Allow the platform to change the state, for example via ACPI
- * _PR0, _PS0 and some such, but do not trust it.
- */
- int ret = platform_pci_power_manageable(dev) ?
- platform_pci_set_power_state(dev, PCI_D0) : 0;
- if (!ret)
- pci_update_current_state(dev, PCI_D0);
- }
+ __pci_start_power_transition(dev, state);
+
/* This device is quirked not to be put into D3, so
don't put it in D3 */
if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
@@ -592,14 +631,8 @@
error = pci_raw_set_power_state(dev, state);
- if (state > PCI_D0 && platform_pci_power_manageable(dev)) {
- /* Allow the platform to finalize the transition */
- int ret = platform_pci_set_power_state(dev, state);
- if (!ret) {
- pci_update_current_state(dev, state);
- error = 0;
- }
- }
+ if (!__pci_complete_power_transition(dev, state))
+ error = 0;
return error;
}