Re: [PATCH] PCI: For d3_delay and d3cold_delay, zero means zero

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Hi Adrian,

On Tue, Mar 14, 2017 at 11:44:56AM +0200, Adrian Hunter wrote:
> Do not sleep at all for the respective cases of d3_delay is zero or
> d3cold_delay is zero.

Can you please include a hint here about (1) what msleep() does with an
argument of zero, and (2) why this change is desirable, e.g., maybe it
makes suspend/resume faster or something?

> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
>  drivers/pci/pci.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7904d02ffdb9..9779483f81fd 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -66,7 +66,8 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
>  	if (delay < pci_pm_d3_delay)
>  		delay = pci_pm_d3_delay;
>  
> -	msleep(delay);
> +	if (delay)
> +		msleep(delay);
>  }
>  
>  #ifdef CONFIG_PCI_DOMAINS
> @@ -827,7 +828,8 @@ static void __pci_start_power_transition(struct pci_dev *dev, pci_power_t state)
>  		 * because have already delayed for the bridge.
>  		 */
>  		if (dev->runtime_d3cold) {
> -			msleep(dev->d3cold_delay);
> +			if (dev->d3cold_delay)
> +				msleep(dev->d3cold_delay);
>  			/*
>  			 * When powering on a bridge from D3cold, the
>  			 * whole hierarchy may be powered on into
> -- 
> 1.9.1
> 



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