PM / Runtime: Remove idle notification after failing suspend

If runtime suspend of a device fails returning -EAGAIN or -EBUSY,
which means that it's safe to try to suspend it again, the PM core
runs the runtime idle helper function for it.  Unfortunately this may
lead to problems, for example for PCI devices whose drivers don't
implement the ->runtime_idle() callback, because in that case the
PCI bus type's ->runtime_idle() always calls pm_runtime_suspend()
for the given device.  Then, if there's an automatic idle
notification after the driver's ->runtime_suspend() returning -EAGAIN
or -EBUSY, it will make the suspend happen again possibly causing a
busy loop to appear.  To avoid that, remove the idle notification
after failing runtime suspend of a device altogether and let the
callers of pm_runtime_suspend() repeat the operation if need be.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Alan Stern <stern@rowland.harvard.edu>

1 files changed, 2 insertions, 9 deletions

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index e957c496a1b..1dd8676d7f5 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -281,7 +281,6 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 {
         int (*callback)(struct device *);
         struct device *parent = NULL;
-        bool notify = false;
         int retval;
 
         dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
@@ -383,13 +382,10 @@ static int rpm_suspend(struct device *dev, int rpmflags)
         if (retval) {
                 __update_runtime_status(dev, RPM_ACTIVE);
                 dev->power.deferred_resume = 0;
-                if (retval == -EAGAIN || retval == -EBUSY) {
-                        if (dev->power.timer_expires == 0)
-                                notify = true;
+                if (retval == -EAGAIN || retval == -EBUSY)
                         dev->power.runtime_error = 0;
-                } else {
+                else
                         pm_runtime_cancel_pending(dev);
-                }
         } else {
  no_callback:
                 __update_runtime_status(dev, RPM_SUSPENDED);
@@ -408,9 +404,6 @@ static int rpm_suspend(struct device *dev, int rpmflags)
                 goto out;
         }
 
-        if (notify)
-                rpm_idle(dev, 0);
-
         if (parent && !parent->power.ignore_children) {
                 spin_unlock_irq(&dev->power.lock);