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Date: Thu, 28 Jun 2012 12:01:02 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Jesse Barnes <jbarnes@...tuousgeek.org>,
Linux PM mailing list <linux-pm@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Matthew Garrett <mjg59@...f.ucam.org>,
"linux-pci" <linux-pci@...r.kernel.org>
Subject: [PATCH] PCI / PM: Restore the original behavior of pci_set_power_state()
From: Rafael J. Wysocki <rjw@...k.pl>
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.
Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
drivers/pci/pci-driver.c | 14 ++++++++------
drivers/pci/pci.c | 19 ++++++++++++++++++-
drivers/pci/pci.h | 1 +
3 files changed, 27 insertions(+), 7 deletions(-)
Index: linux/drivers/pci/pci.c
===================================================================
--- linux.orig/drivers/pci/pci.c
+++ linux/drivers/pci/pci.c
@@ -662,6 +662,19 @@ void pci_update_current_state(struct pci
}
/**
+ * 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.
* @state: State to put the device into.
@@ -707,7 +720,7 @@ static void __pci_start_power_transition
*/
int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state)
{
- return state >= PCI_D0 ?
+ return state > PCI_D0 ?
pci_platform_power_transition(dev, state) : -EINVAL;
}
EXPORT_SYMBOL_GPL(__pci_complete_power_transition);
@@ -744,6 +757,10 @@ int pci_set_power_state(struct pci_dev *
*/
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
Index: linux/drivers/pci/pci-driver.c
===================================================================
--- linux.orig/drivers/pci/pci-driver.c
+++ linux/drivers/pci/pci-driver.c
@@ -459,16 +459,17 @@ static int pci_restore_standard_config(s
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).
@@ -1050,7 +1051,8 @@ static int pci_pm_runtime_resume(struct
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);
Index: linux/drivers/pci/pci.h
===================================================================
--- linux.orig/drivers/pci/pci.h
+++ linux/drivers/pci/pci.h
@@ -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);
--
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