6.14-stable review patch. If anyone has any objections, please let me know.
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From: Xu Yang xu.yang_2@nxp.com
[ Upstream commit e8195f0630f1c4c2465074fe81b5fda19efd3148 ]
Currently, if power.no_callbacks is set, device_prepare() will also set power.direct_complete for the device. If power.direct_complete is set in device_resume(), the clearing of power.is_prepared will be skipped and if new children appear under the device at that point, a warning will be printed.
After commit (f76b168b6f11 PM: Rename dev_pm_info.in_suspend to is_prepared), power.is_prepared is generally cleared in device_resume() before invoking the resume callback for the device which allows that callback to add new children without triggering the warning, but this does not happen for devices with power.direct_complete set.
This problem is visible in USB where usb_set_interface() can be called before device_complete() clears power.is_prepared for interface devices and since ep devices are added then, the warning is printed:
usb 1-1: reset high-speed USB device number 3 using ci_hdrc ep_81: PM: parent 1-1:1.1 should not be sleeping PM: resume devices took 0.936 seconds
Since it is legitimate to add the ep devices at that point, the warning above is not particularly useful, so get rid of it by clearing power.is_prepared in device_resume() for devices with power.direct_complete set if they have no PM callbacks, in which case they need not actually resume for the new children to work.
Suggested-by: Rafael J. Wysocki rafael@kernel.org Signed-off-by: Xu Yang xu.yang_2@nxp.com Link: https://patch.msgid.link/20250224070049.3338646-1-xu.yang_2@nxp.com [ rjw: New subject, changelog edits, rephrased new code comment ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/power/main.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 23be2d1b04079..37fe251b4c591 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -933,6 +933,13 @@ static void device_resume(struct device *dev, pm_message_t state, bool async) goto Complete;
if (dev->power.direct_complete) { + /* + * Allow new children to be added under the device after this + * point if it has no PM callbacks. + */ + if (dev->power.no_pm_callbacks) + dev->power.is_prepared = false; + /* Match the pm_runtime_disable() in device_suspend(). */ pm_runtime_enable(dev); goto Complete;