Messages in this thread | | | Date | Wed, 20 Jun 2012 10:58:25 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend after abort |
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On Tue, 19 Jun 2012, Mandeep Singh Baines wrote:
> __device_suspend() must always send a completion. Otherwise, parent > devices will wait forever. > > Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and > system sleep (v2)", introduced a regression by short-circuiting the > complete_all() for certain error cases. > > This patch fixes the bug by always signalling a completion. > > Addresses http://crosbug.com/31972 > > Tested by injecting an abort via the following patch: > > diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c > index a004db3..e5a6fce 100644 > --- a/drivers/usb/core/hcd-pci.c > +++ b/drivers/usb/core/hcd-pci.c > @@ -21,6 +21,7 @@ > #include <linux/pci.h> > #include <linux/usb.h> > #include <linux/usb/hcd.h> > +#include <linux/string.h> > > #include <asm/io.h> > #include <asm/irq.h> > @@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event) > > static int hcd_pci_suspend(struct device *dev) > { > + if (!strcmp("0000:00:1d.3", dev_name(dev))) > + return -EBUSY; > return suspend_common(dev, device_may_wakeup(dev)); > }
When you include one patch in front of another like this, doesn't it confuse the automatic tools? You might end up getting both changes include in the final commit. :-)
> drivers/base/power/main.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > index e0fb5b0..9cb845e 100644 > --- a/drivers/base/power/main.c > +++ b/drivers/base/power/main.c > @@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) > dpm_wait_for_children(dev, async); > > if (async_error) > - return 0; > + goto Complete; > > pm_runtime_get_noresume(dev); > if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) > @@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) > if (pm_wakeup_pending()) { > pm_runtime_put_sync(dev); > async_error = -EBUSY; > - return 0; > + goto Complete; > } > > device_lock(dev); > @@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) > } > > device_unlock(dev); > + > + Complete: > complete_all(&dev->power.completion); > > if (error) {
Otherwise this looks right to me.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
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