linux-kernel - Re: [PATCH 6/9] PM: Add a switch for disabling/enabling asynchronous suspend/resume

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Message-ID: <20090910102653.GA30778@atrey.karlin.mff.cuni.cz>
Date:	Thu, 10 Sep 2009 12:26:53 +0200
From:	Pavel Machek <pavel@....cz>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	linux-pm <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PCI <linux-pci@...r.kernel.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Len Brown <lenb@...nel.org>, Zhang Rui <rui.zhang@...el.com>,
	Alan Stern <stern@...land.harvard.edu>,
	Arjan van de Ven <arjan@...radead.org>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH 6/9] PM: Add a switch for disabling/enabling asynchronous suspend/resume

> From: Rafael J. Wysocki <rjw@...k.pl>
> 
> Add sysfs attribute kernel/power/pm_async allowing the user space to
> disable and enable async suspend/resume of devices.

for bisect reasons, should this go before 5?

> 
> Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
> ---
>  drivers/base/power/main.c  |   13 +++++++------
>  drivers/base/power/power.h |    6 +++---
>  kernel/power/main.c        |   31 ++++++++++++++++++++++++++++++-
>  3 files changed, 40 insertions(+), 10 deletions(-)
> 
> Index: linux-2.6/kernel/power/main.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/main.c
> +++ linux-2.6/kernel/power/main.c
> @@ -44,6 +44,32 @@ int pm_notifier_call_chain(unsigned long
>  			== NOTIFY_BAD) ? -EINVAL : 0;
>  }
>  
> +/* If set, devices may be suspended and resumed asynchronously. */
> +int pm_async_enabled = 1;
> +
> +static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			     char *buf)
> +{
> +	return sprintf(buf, "%d\n", pm_async_enabled);
> +}
> +
> +static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
> +			      const char *buf, size_t n)
> +{
> +	unsigned long val;
> +
> +	if (strict_strtoul(buf, 10, &val))
> +		return -EINVAL;
> +
> +	if (val > 1)
> +		return -EINVAL;
> +
> +	pm_async_enabled = val;
> +	return n;
> +}
> +
> +power_attr(pm_async);
> +
>  #ifdef CONFIG_PM_DEBUG
>  int pm_test_level = TEST_NONE;
>  
> @@ -208,9 +234,12 @@ static struct attribute * g[] = {
>  #ifdef CONFIG_PM_TRACE
>  	&pm_trace_attr.attr,
>  #endif
> -#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
> +#ifdef CONFIG_PM_SLEEP
> +	&pm_async_attr.attr,
> +#ifdef CONFIG_PM_DEBUG
>  	&pm_test_attr.attr,
>  #endif
> +#endif
>  	NULL,
>  };
>  
> Index: linux-2.6/drivers/base/power/main.c
> ===================================================================
> --- linux-2.6.orig/drivers/base/power/main.c
> +++ linux-2.6/drivers/base/power/main.c
> @@ -235,7 +235,7 @@ static int device_pm_wait_fn(struct devi
>   */
>  static void device_pm_wait_for_masters(struct device *slave)
>  {
> -	if (!pm_trace_enabled)
> +	if (pm_async_enabled && !pm_trace_enabled)
>  		device_for_each_master(slave, slave, device_pm_wait_fn);
>  }
>  
> @@ -245,7 +245,8 @@ static void device_pm_wait_for_masters(s
>   */
>  static void device_pm_wait_for_slaves(struct device *master)
>  {
> -	device_for_each_slave(master, master, device_pm_wait_fn);
> +	if (pm_async_enabled)
> +		device_for_each_slave(master, master, device_pm_wait_fn);
>  }
>  
>  /**
> @@ -560,7 +561,7 @@ static int device_resume_noirq(struct de
>  	if (pm_op_started(dev))
>  		return 0;
>  
> -	if (dev->power.async_suspend && !pm_trace_enabled) {
> +	if (pm_async_enabled && !pm_trace_enabled && dev->power.async_suspend) {
>  		async_schedule(async_resume_noirq, dev);
>  		return 0;
>  	}
> @@ -719,7 +720,7 @@ static int device_resume(struct device *
>  	if (pm_op_started(dev))
>  		return 0;
>  
> -	if (dev->power.async_suspend && !pm_trace_enabled) {
> +	if (pm_async_enabled && !pm_trace_enabled && dev->power.async_suspend) {
>  		get_device(dev);
>  		async_schedule(async_resume, dev);
>  		return 0;
> @@ -965,7 +966,7 @@ static int device_suspend_noirq(struct d
>  	if (pm_op_started(dev))
>  		return 0;
>  
> -	if (dev->power.async_suspend) {
> +	if (pm_async_enabled && dev->power.async_suspend) {
>  		async_schedule(async_suspend_noirq, dev);
>  		return 0;
>  	}
> @@ -1139,7 +1140,7 @@ static int device_suspend(struct device 
>  	if (pm_op_started(dev))
>  		return 0;
>  
> -	if (dev->power.async_suspend) {
> +	if (pm_async_enabled && dev->power.async_suspend) {
>  		get_device(dev);
>  		async_schedule(async_suspend, dev);
>  		return 0;
> Index: linux-2.6/drivers/base/power/power.h
> ===================================================================
> --- linux-2.6.orig/drivers/base/power/power.h
> +++ linux-2.6/drivers/base/power/power.h
> @@ -16,10 +16,10 @@ static inline void pm_runtime_remove(str
>  
>  #ifdef CONFIG_PM_SLEEP
>  
> -/*
> - * main.c
> - */
> +/* kernel/power/main.c */
> +extern int pm_async_enabled;
>  
> +/* drivers/base/power/main.c */
>  extern struct list_head dpm_list;	/* The active device list */
>  
>  static inline struct device *to_device(struct list_head *entry)

-- 
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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