Re: [PATCH v2 2/2] Adds new device resume mode in PM core, async plus non-blocking

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, May 17, 2013 at 07:05:33PM +0000, Brandt, Todd E wrote:
> Updates the drivers/base/power subsystem to allow any devices which
> have registred as asynchronous and who have not registered "complete"
> callbacks to be non-blocking. i.e system resume can finish and return
> control to the user while these devices continue resuming.
> 
> Changelog:
> v2:
>         - Updated patch submission. Incorporates comments from Tejun Heo.   
>           Fixed comment format, removed camelcase. No functional changes.
> 
> Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
> ---
>  drivers/base/power/main.c |   20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 2b7f77d..1b16379 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -713,7 +713,6 @@ void dpm_resume(pm_message_t state)
>  		put_device(dev);
>  	}
>  	mutex_unlock(&dpm_list_mtx);
> -	async_synchronize_full();
>  	dpm_show_time(starttime, state, NULL);
>  }
>  
> @@ -726,11 +725,14 @@ static void device_complete(struct device *dev, pm_message_t state)
>  {
>  	void (*callback)(struct device *) = NULL;
>  	char *info = NULL;
> +	bool hascb = false;

"hascb"?  Please spell out what this is.

>  
>  	if (dev->power.syscore)
>  		return;
>  
> -	device_lock(dev);
> + docomplete:
> +	if (hascb)
> +		device_lock(dev);
>  
>  	if (dev->pm_domain) {
>  		info = "completing power domain ";
> @@ -751,13 +753,21 @@ static void device_complete(struct device *dev, pm_message_t state)
>  		callback = dev->driver->pm->complete;
>  	}
>  
> +	/*
> +	 * if a callback exists, lock the device and call it
> +	 * otherwise don't even lock/unlock the device
> +	 */
>  	if (callback) {
> +		if (!hascb) {
> +			hascb = true;
> +			goto docomplete;

You want to jump backwards?  This isn't the scheduler, please, you can
do better here.

thanks,

greg k-h