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Subject[RFC][PATCH 1/2] PCI PM: Export platform_pci_set_power_state()
Date
From: Rafael J. Wysocki <rjw@sisk.pl>

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, change platform_pci_set_power_state() into an
exported function so that the radeonfb driver can use it directly
instead of calling it via pci_set_power_state().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/pci/pci.c | 68 +++++++++++++++++++++++++++++-----------------------
include/linux/pci.h | 1
2 files changed, 40 insertions(+), 29 deletions(-)
Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -398,12 +398,6 @@ static inline bool platform_pci_power_ma
return pci_platform_pm ? pci_platform_pm->is_manageable(dev) : false;
}

-static inline int platform_pci_set_power_state(struct pci_dev *dev,
- pci_power_t t)
-{
- return pci_platform_pm ? pci_platform_pm->set_state(dev, t) : -ENOSYS;
-}
-
static inline pci_power_t platform_pci_choose_state(struct pci_dev *dev)
{
return pci_platform_pm ?
@@ -540,6 +534,31 @@ void pci_update_current_state(struct pci
}

/**
+ * platform_pci_set_power_state - Call platform to change device power state
+ * @dev: PCI device to handle
+ * @state: State to put the device into
+ *
+ * Allow the platform to change the power state of the device, for example via
+ * ACPI _PR0, _PS0 or some such.
+ */
+int platform_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
+{
+ int error = 0;
+
+ if (!pci_platform_pm)
+ return -ENOSYS;
+
+ if (pci_platform_pm->is_manageable(dev))
+ error = pci_platform_pm->set_state(dev, state);
+
+ if (!error)
+ pci_update_current_state(dev, state);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(platform_pci_set_power_state);
+
+/**
* 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.
@@ -556,7 +575,7 @@ void pci_update_current_state(struct pci
*/
int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
{
- int error;
+ int error, platform_error = -ENODEV;

/* bound the state we're entering */
if (state > PCI_D3hot)
@@ -570,36 +589,27 @@ int pci_set_power_state(struct pci_dev *
* it into D0 (which would only happen on boot).
*/
return 0;
+ else if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
+ /*
+ * This device is quirked not to be put into D3, so don't put it
+ * in D3
+ */
+ return 0;

/* Check if we're already there */
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);
- }
- /* 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))
- return 0;
+ if (state == PCI_D0)
+ platform_error = platform_pci_set_power_state(dev, PCI_D0);

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 (state > PCI_D0)
+ platform_error = platform_pci_set_power_state(dev, state);
+
+ if (!platform_error)
+ error = 0;

return error;
}
Index: linux-2.6/include/linux/pci.h
===================================================================
--- linux-2.6.orig/include/linux/pci.h
+++ linux-2.6/include/linux/pci.h
@@ -689,6 +689,7 @@ size_t pci_get_rom_size(struct pci_dev *
/* Power management related routines */
int pci_save_state(struct pci_dev *dev);
int pci_restore_state(struct pci_dev *dev);
+int platform_pci_set_power_state(struct pci_dev *dev, pci_power_t state);
int pci_set_power_state(struct pci_dev *dev, pci_power_t state);
pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);
bool pci_pme_capable(struct pci_dev *dev, pci_power_t state);

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