Commit 0e5dd46b authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 931ff68a

drivers/pci/pci.c

+51 −18
Original line number Diff line number Diff line
@@ -539,6 +539,53 @@ void pci_update_current_state(struct pci_dev *dev, pci_power_t state) 
	}

}



/**

 * 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.
@@ -575,16 +622,8 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state) 
	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 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state) 


	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);

	if (!__pci_complete_power_transition(dev, state))

		error = 0;

		}

	}



	return error;

}

include/linux/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -689,6 +689,7 @@ size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size); 
/* Power management related routines */

int pci_save_state(struct pci_dev *dev);

int pci_restore_state(struct pci_dev *dev);

int __pci_complete_power_transition(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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