linux-kernel - Re: [PATCHv3 5/5] arm: omap2+: omap_device: remove no_idle_on

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Message-ID: <87d2tj378q.fsf@linaro.org>
Date:	Wed, 24 Apr 2013 15:15:49 -0700
From:	Kevin Hilman <khilman@...aro.org>
To:	Sourav Poddar <sourav.poddar@...com>
Cc:	<gregkh@...uxfoundation.org>, <tony@...mide.com>,
	<rmk+kernel@....linux.org.uk>, <linux-serial@...r.kernel.org>,
	<linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Felipe Balbi <balbi@...com>, Rajendra nayak <rnayak@...com>,
	Grygorii Strashko <grygorii.strashko@...com>
Subject: Re: [PATCHv3 5/5] arm: omap2+: omap_device: remove no_idle_on_suspend

Sourav Poddar <sourav.poddar@...com> writes:

> Remove "no_idle_on_suspend" check, since respective
> driver should be able to prevent idling of a
> device whenever required.
>
> Driver's can get same behavior by just returning -EBUSY
> from their ->runtime_suspend only during suspend.
>
> Cc: Santosh Shilimkar <santosh.shilimkar@...com>
> Cc: Felipe Balbi <balbi@...com>
> Cc: Rajendra nayak <rnayak@...com>
> Cc: Grygorii Strashko <grygorii.strashko@...com>
> Signed-off-by: Sourav Poddar <sourav.poddar@...com>
> Reviewed-by: Felipe Balbi <balbi@...com>
> ---
>  arch/arm/mach-omap2/omap_device.c |   12 +++---------
>  arch/arm/mach-omap2/omap_device.h |   10 ----------
>  2 files changed, 3 insertions(+), 19 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
> index 381be7a..2043d71 100644
> --- a/arch/arm/mach-omap2/omap_device.c
> +++ b/arch/arm/mach-omap2/omap_device.c
> @@ -170,9 +170,6 @@ static int omap_device_build_from_dt(struct platform_device *pdev)
>  			r->name = dev_name(&pdev->dev);
>  	}
>  
> -	if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
> -		omap_device_disable_idle_on_suspend(pdev);
> -
>  	pdev->dev.pm_domain = &omap_device_pm_domain;
>  
>  odbfd_exit1:
> @@ -620,11 +617,9 @@ static int _od_suspend_noirq(struct device *dev)
>  	ret = pm_generic_suspend_noirq(dev);
>  
>  	if (!ret && !pm_runtime_status_suspended(dev)) {
> -		if (pm_generic_runtime_suspend(dev) == 0) {
> -			if (!(od->flags & OMAP_DEVICE_NO_IDLE_ON_SUSPEND))
> -				omap_device_idle(pdev);
> +		if (pm_generic_runtime_suspend(dev) == 0)
> +			omap_device_idle(pdev);
>  			od->flags |= OMAP_DEVICE_SUSPENDED;
> -		}

Look closely at the if statement, followed by more than one line, and
the braces removed.

That means that od->flag will be set, even when omap_device_idle() was
not called.  Which in turn means that upon resume, omap_device_enable()
will be called on a device that has not had omap_device_idle() called,
which means there would be WARNs coming from omap_device due to the
mismatch.

Hmm... this does not instill confidence that this code has been tested.

Kevin


>  	}
>  
>  	return ret;
> @@ -638,8 +633,7 @@ static int _od_resume_noirq(struct device *dev)
>  	if ((od->flags & OMAP_DEVICE_SUSPENDED) &&
>  	    !pm_runtime_status_suspended(dev)) {
>  		od->flags &= ~OMAP_DEVICE_SUSPENDED;
> -		if (!(od->flags & OMAP_DEVICE_NO_IDLE_ON_SUSPEND))
> -			omap_device_enable(pdev);
> +		omap_device_enable(pdev);
>  		pm_generic_runtime_resume(dev);
>  	}
>  
> diff --git a/arch/arm/mach-omap2/omap_device.h b/arch/arm/mach-omap2/omap_device.h
> index 044c31d..17ca1ae 100644
> --- a/arch/arm/mach-omap2/omap_device.h
> +++ b/arch/arm/mach-omap2/omap_device.h
> @@ -38,7 +38,6 @@ extern struct dev_pm_domain omap_device_pm_domain;
>  
>  /* omap_device.flags values */
>  #define OMAP_DEVICE_SUSPENDED		BIT(0)
> -#define OMAP_DEVICE_NO_IDLE_ON_SUSPEND	BIT(1)
>  
>  /**
>   * struct omap_device - omap_device wrapper for platform_devices
> @@ -101,13 +100,4 @@ static inline struct omap_device *to_omap_device(struct platform_device *pdev)
>  {
>  	return pdev ? pdev->archdata.od : NULL;
>  }
> -
> -static inline
> -void omap_device_disable_idle_on_suspend(struct platform_device *pdev)
> -{
> -	struct omap_device *od = to_omap_device(pdev);
> -
> -	od->flags |= OMAP_DEVICE_NO_IDLE_ON_SUSPEND;
> -}
> -
>  #endif
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