Re: [PATCH] PM: sleep: core: Set is_prepared to false before checking direct_complete

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Feb 11, 2025 at 11:44:23AM +0800, Xu Yang wrote:
> Currently, if power.no_callbacks is true for a device, device_prepare()
> will also set power.direct_complete to true. When device_resume() check
> power.direct_complete, setting power.is_prepared will be skipped if it
> can directly complete. This will cause a warning when add new devices
> during resume() stage.
> 
> Although power.is_prepared should be cleared in complete() state, commit
> (f76b168b6f11 PM: Rename dev_pm_info.in_suspend to is_prepared) allow
> clear it in earlier resume() stage. However, we need set is_prepared to
> false before checking direct_complete after including direct complete
> support.
> 
> Take USB as example:
> The usb_interface is such a device which setting power.no_callbacks to
> true. Then if the user call usb_set_interface() during resume() stage,
> the kernel will print below warning since the system will create and
> add ep devices.
> 
> [  186.461414] usb 1-1: reset high-speed USB device number 3 using ci_hdrc
> [  187.102681]  ep_81: PM: parent 1-1:1.1 should not be sleeping
> [  187.105010] PM: resume devices took 0.936 seconds
> 
> Fixes: aae4518b3124 ("PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily")
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
> ---
>  drivers/base/power/main.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 40e1d8d8a589..69d0f9ca7051 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -929,6 +929,12 @@ static void device_resume(struct device *dev, pm_message_t state, bool async)
>  	if (dev->power.syscore)
>  		goto Complete;
>  
> +	/*
> +	 * This is a fib.  But we'll allow new children to be added below
> +	 * a resumed device, even if the device hasn't been completed yet.
> +	 */
> +	dev->power.is_prepared = false;
> +
>  	if (dev->power.direct_complete) {
>  		/* Match the pm_runtime_disable() in device_suspend(). */
>  		pm_runtime_enable(dev);
> @@ -941,12 +947,6 @@ static void device_resume(struct device *dev, pm_message_t state, bool async)
>  	dpm_watchdog_set(&wd, dev);
>  	device_lock(dev);
>  
> -	/*
> -	 * This is a fib.  But we'll allow new children to be added below
> -	 * a resumed device, even if the device hasn't been completed yet.
> -	 */
> -	dev->power.is_prepared = false;
> -
>  	if (!dev->power.is_suspended)
>  		goto Unlock;
>  
> -- 
> 2.34.1
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
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