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| author | Rafael J. Wysocki <rjw@sisk.pl> | 2011-06-21 23:47:15 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rjw@sisk.pl> | 2011-06-21 23:47:15 +0200 |
| commit | a5f76d5eba157bf637beb2dd18026db2917c512e (patch) | |
| tree | 0f23e14459b8324e965c6a82d8b74dde1b4018e4 /drivers/pci | |
| parent | ca9c6890b598997165a7c85c001f382c910f12b0 (diff) | |
| download | lwn-a5f76d5eba157bf637beb2dd18026db2917c512e.tar.gz lwn-a5f76d5eba157bf637beb2dd18026db2917c512e.zip | |
PCI / PM: Block races between runtime PM and system sleep
After commit e8665002477f0278f84f898145b1f141ba26ee26
(PM: Allow pm_runtime_suspend() to succeed during system suspend) it
is possible that a device resumed by the pm_runtime_resume(dev) in
pci_pm_prepare() will be suspended immediately from a work item,
timer function or otherwise, defeating the very purpose of calling
pm_runtime_resume(dev) from there. To prevent that from happening
it is necessary to increment the runtime PM usage counter of the
device by replacing pm_runtime_resume() with pm_runtime_get_sync().
Moreover, the incremented runtime PM usage counter has to be
decremented by the corresponding pci_pm_complete(), via
pm_runtime_put_sync().
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/pci-driver.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 135df164a4c1..46767c53917a 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -624,7 +624,7 @@ static int pci_pm_prepare(struct device *dev) * system from the sleep state, we'll have to prevent it from signaling * wake-up. */ - pm_runtime_resume(dev); + pm_runtime_get_sync(dev); if (drv && drv->pm && drv->pm->prepare) error = drv->pm->prepare(dev); @@ -638,6 +638,8 @@ static void pci_pm_complete(struct device *dev) if (drv && drv->pm && drv->pm->complete) drv->pm->complete(dev); + + pm_runtime_put_sync(dev); } #else /* !CONFIG_PM_SLEEP */ |