| Message ID | 12627587.O9o76ZdvQC@rjwysocki.net (mailing list archive) |
|---|---|
| State | In Next |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | [v1] PM: sleep: Fix handling devices with direct_complete set on errors | expand |
On Thu, Mar 13, 2025 at 9:00 AM Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > When dpm_suspend() fails, some devices with power.direct_complete set > may not have been handled by device_suspend() yet, so runtime PM has > not been disabled for them yet even though power.direct_complete is set. > > Since device_resume() expects that runtime PM has been disabled for all > devices with power.direct_complete set, it will attempt to reenable > runtime PM for the devices that have not been processed by device_suspend() > which does not make sense. Had those devices had runtime PM disabled > before device_suspend() had run, device_resume() would have inadvertently > enable runtime PM for them, but this is not expected to happen because > it would require ->prepare() callbacks to return positive values for > devices with runtime PM disabled, which would be invalid. > > In practice, this issue is most likely benign because pm_runtime_enable() > will not allow the "disable depth" counter to underflow, but it causes a > warning message to be printed for each affected device. > > To allow device_resume() to distinguish the "direct complete" devices > that have been processed by device_suspend() from those which have not > been handled by it, make device_suspend() set power.is_suspended for > "direct complete" devices. > > Next, move the power.is_suspended check in device_resume() before the > power.direct_complete check in it to make it skip the "direct complete" > devices that have not been handled by device_suspend(). > > This change is based on a preliminary patch from Saravana Kannan. > > Fixes: aae4518b3124 ("PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily") > Link: https://lore.kernel.org/linux-pm/20241114220921.2529905-2-saravanak@google.com/ > Reported-by: Saravana Kannan <saravanak@google.com> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Saravana Kannan <saravanak@google.com> > --- > drivers/base/power/main.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > --- a/drivers/base/power/main.c > +++ b/drivers/base/power/main.c > @@ -938,6 +938,9 @@ > if (dev->power.syscore) > goto Complete; > > + if (!dev->power.is_suspended) > + goto Complete; > + > if (dev->power.direct_complete) { > /* > * Allow new children to be added under the device after this > @@ -963,9 +966,6 @@ > */ > dev->power.is_prepared = false; > > - if (!dev->power.is_suspended) > - goto Unlock; > - > if (dev->pm_domain) { > info = "power domain "; > callback = pm_op(&dev->pm_domain->ops, state); > @@ -1005,7 +1005,6 @@ > error = dpm_run_callback(callback, dev, state, info); > dev->power.is_suspended = false; > > - Unlock: > device_unlock(dev); > dpm_watchdog_clear(&wd); > > @@ -1669,6 +1668,7 @@ > pm_runtime_disable(dev); > if (pm_runtime_status_suspended(dev)) { > pm_dev_dbg(dev, state, "direct-complete "); > + dev->power.is_suspended = true; > goto Complete; > } > > > >
--- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -938,6 +938,9 @@ if (dev->power.syscore) goto Complete; + if (!dev->power.is_suspended) + goto Complete; + if (dev->power.direct_complete) { /* * Allow new children to be added under the device after this @@ -963,9 +966,6 @@ */ dev->power.is_prepared = false; - if (!dev->power.is_suspended) - goto Unlock; - if (dev->pm_domain) { info = "power domain "; callback = pm_op(&dev->pm_domain->ops, state); @@ -1005,7 +1005,6 @@ error = dpm_run_callback(callback, dev, state, info); dev->power.is_suspended = false; - Unlock: device_unlock(dev); dpm_watchdog_clear(&wd); @@ -1669,6 +1668,7 @@ pm_runtime_disable(dev); if (pm_runtime_status_suspended(dev)) { pm_dev_dbg(dev, state, "direct-complete "); + dev->power.is_suspended = true; goto Complete; }