From 03f1444016b71feffa1dfb8a51f15ba592f94b13 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 13 Mar 2025 17:00:00 +0100 Subject: [PATCH] PM: sleep: Fix handling devices with direct_complete set on errors 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 Signed-off-by: Rafael J. Wysocki Reviewed-by: Saravana Kannan Link: https://patch.msgid.link/12627587.O9o76ZdvQC@rjwysocki.net --- drivers/base/power/main.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 1b0eb83f70615..ad50018b80479 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -938,6 +938,9 @@ static void device_resume(struct device *dev, pm_message_t state, bool async) 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 @@ static void device_resume(struct device *dev, pm_message_t state, bool async) */ 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 @@ static void device_resume(struct device *dev, pm_message_t state, bool async) 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 @@ static int device_suspend(struct device *dev, pm_message_t state, bool async) pm_runtime_disable(dev); if (pm_runtime_status_suspended(dev)) { pm_dev_dbg(dev, state, "direct-complete "); + dev->power.is_suspended = true; goto Complete; } -- 2.39.5