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authorRafael J. Wysocki <rjw@sisk.pl>2012-07-12 11:51:48 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-16 19:25:49 -0700
commiteed5d2150752bd08b22333d739f3120151773d28 (patch)
treea9bcdd279da2e39951bb588e51f075aa271088c5
parenteab072609e11a357181806ab5a5c309ef6eb76f5 (diff)
downloadop-kernel-dev-eed5d2150752bd08b22333d739f3120151773d28.zip
op-kernel-dev-eed5d2150752bd08b22333d739f3120151773d28.tar.gz
PM / Runtime: Do not increment device usage counts before probing
The pm_runtime_get_noresume() calls before really_probe() and before executing __device_attach() for each driver on the device's bus cause problems to happen if probing fails and if the driver has enabled runtime PM for the device in its .probe() callback. Namely, in that case, if the device has been resumed by the driver after enabling its runtime PM and if it turns out that .probe() should return an error, the driver is supposed to suspend the device and disable its runtime PM before exiting .probe(). However, because the device's runtime PM usage counter was incremented by the core before calling .probe(), the driver's attempt to suspend the device will not succeed and the device will remain in the full-power state after the failing .probe() has returned. To fix this issue, remove the pm_runtime_get_noresume() calls from driver_probe_device() and from device_attach() and replace the corresponding pm_runtime_put_sync() calls with pm_runtime_idle() to preserve the existing behavior (which is to check if the device is idle and to suspend it eventually in that case after probing). Reported-and-tested-by: Kevin Hilman <khilman@ti.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/base/dd.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 9b0aca4..e3bbed8 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -369,10 +369,9 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
drv->bus->name, __func__, dev_name(dev), drv->name);
- pm_runtime_get_noresume(dev);
pm_runtime_barrier(dev);
ret = really_probe(dev, drv);
- pm_runtime_put_sync(dev);
+ pm_runtime_idle(dev);
return ret;
}
@@ -419,9 +418,8 @@ int device_attach(struct device *dev)
ret = 0;
}
} else {
- pm_runtime_get_noresume(dev);
ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
- pm_runtime_put_sync(dev);
+ pm_runtime_idle(dev);
}
out_unlock:
device_unlock(dev);
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