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Commit db288c9c authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Bjorn Helgaas
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PCI / PM: restore the original behavior of pci_set_power_state() 



Commit cc2893b6 (PCI: Ensure we re-enable devices on resume)
addressed the problem with USB not being powered after resume on
recent Lenovo machines, but it did that in a suboptimal way.
Namely, it should have changed the relevant code paths only,
which are pci_pm_resume_noirq() and pci_pm_restore_noirq() supposed
to restore the device's power and standard configuration registers
after system resume from suspend or hibernation.  Instead, however,
it modified pci_set_power_state() which is executed in several
other situations too.  That resulted in some undesirable effects,
like attempting to change a device's power state in the same way
multiple times in a row (up to as many as 4 times in a row in the
snd_hda_intel driver).

Fix the bug addressed by commit cc2893b6 in an alternative way,
by forcibly powering up all devices in pci_pm_default_resume_early(),
which is called by pci_pm_resume_noirq() and pci_pm_restore_noirq()
to restore the device's power and standard configuration registers,
and modifying pci_pm_runtime_resume() to avoid the forcible power-up
if not necessary.  Then, revert the changes made by commit cc2893b6
to make the confusion introduced by it go away.

Acked-by: default avatarMatthew Garrett <mjg@redhat.com>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 448bd857

drivers/pci/pci-driver.c

+8 −6
Original line number Diff line number Diff line
@@ -459,16 +459,17 @@ static int pci_restore_standard_config(struct pci_dev *pci_dev) 
	return 0;

}



#endif



#ifdef CONFIG_PM_SLEEP



static void pci_pm_default_resume_early(struct pci_dev *pci_dev)

{

	pci_restore_standard_config(pci_dev);

	pci_power_up(pci_dev);

	pci_restore_state(pci_dev);

	pci_fixup_device(pci_fixup_resume_early, pci_dev);

}



#endif



#ifdef CONFIG_PM_SLEEP



/*

 * Default "suspend" method for devices that have no driver provided suspend,

 * or not even a driver at all (second part).
@@ -1054,7 +1055,8 @@ static int pci_pm_runtime_resume(struct device *dev) 
	if (!pm || !pm->runtime_resume)

		return -ENOSYS;



	pci_pm_default_resume_early(pci_dev);

	pci_restore_standard_config(pci_dev);

	pci_fixup_device(pci_fixup_resume_early, pci_dev);

	__pci_enable_wake(pci_dev, PCI_D0, true, false);

	pci_fixup_device(pci_fixup_resume, pci_dev);

drivers/pci/pci.c

+18 −1
Original line number Diff line number Diff line
@@ -672,6 +672,19 @@ void pci_update_current_state(struct pci_dev *dev, pci_power_t state) 
	}

}



/**

 * pci_power_up - Put the given device into D0 forcibly

 * @dev: PCI device to power up

 */

void pci_power_up(struct pci_dev *dev)

{

	if (platform_pci_power_manageable(dev))

		platform_pci_set_power_state(dev, PCI_D0);



	pci_raw_set_power_state(dev, PCI_D0);

	pci_update_current_state(dev, PCI_D0);

}



/**

 * pci_platform_power_transition - Use platform to change device power state

 * @dev: PCI device to handle.
@@ -762,7 +775,7 @@ int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state) 
{

	int ret;



	if (state < PCI_D0)

	if (state <= PCI_D0)

		return -EINVAL;

	ret = pci_platform_power_transition(dev, state);

	/* Power off the bridge may power off the whole hierarchy */
@@ -804,6 +817,10 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state) 
		 */

		return 0;



	/* Check if we're already there */

	if (dev->current_state == state)

		return 0;



	__pci_start_power_transition(dev, state);



	/* This device is quirked not to be put into D3, so

drivers/pci/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ struct pci_platform_pm_ops { 


extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);

extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state);

extern void pci_power_up(struct pci_dev *dev);

extern void pci_disable_enabled_device(struct pci_dev *dev);

extern int pci_finish_runtime_suspend(struct pci_dev *dev);

extern int __pci_pme_wakeup(struct pci_dev *dev, void *ign);