FROMLIST: PM / sleep: don't suspend parent when async child suspend_{noirq,late}...

Consider two devices, A and B, where B is a child of A, and B utilizes
asynchronous suspend (it does not matter whether A is sync or async). If
B fails to suspend_noirq() or suspend_late(), or is interrupted by a
wakeup (pm_wakeup_pending()), then it aborts and sets the async_error
variable. However, device A does not (immediately) check the async_error
variable; it may continue to run its own suspend_noirq()/suspend_late()
callback. This is bad.

We can resolve this problem by checking the async_error flag after
waiting for children to suspend, using the same logic for the noirq and
late suspend cases as we already do for __device_suspend().

It's easy to observe this erroneous behavior by, for example, forcing a
device to sleep a bit in its suspend_noirq() (to ensure the parent is
waiting for the child to complete), then return an error, and watch the
parent suspend_noirq() still get called. (Or similarly, fake a wakeup
event at the right (or is it wrong?) time.)

Change-Id: I9f6d9a599b45aaeb2debccc50a47525f138ad07e
Fixes: de377b397272 ("PM / sleep: Asynchronous threads for suspend_late")
Fixes: 28b6fd6e3779 ("PM / sleep: Asynchronous threads for suspend_noirq")
Reported-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index d388edadfb6ad6fcdce33ea5d615c40528c33846..982f586e9290b5acd65c713b9a5742e785bfd863 100644 (file)
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1038,6 +1038,9 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
 
        dpm_wait_for_children(dev, async);
 
+       if (async_error)
+               goto Complete;
+
        if (dev->pm_domain) {
                info = "noirq power domain ";
                callback = pm_noirq_op(&dev->pm_domain->ops, state);
@@ -1185,6 +1188,9 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
 
        dpm_wait_for_children(dev, async);
 
+       if (async_error)
+               goto Complete;
+
        if (dev->pm_domain) {
                info = "late power domain ";
                callback = pm_late_early_op(&dev->pm_domain->ops, state);