linux-kernel - Re: [PATCH 2/3][v3] Thermal: handle thermal zone device properly during system sleep

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Message-ID: <20151231184825.GA14486@localhost.localdomain>
Date:	Thu, 31 Dec 2015 10:48:27 -0800
From:	Eduardo Valentin <edubezval@...il.com>
To:	Chen Yu <yu.c.chen@...el.com>
Cc:	rui.zhang@...el.com, javi.merino@....com, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH 2/3][v3] Thermal: handle thermal zone device properly
 during system sleep

On Fri, Oct 30, 2015 at 04:31:58PM +0800, Chen Yu wrote:
> From: Zhang Rui <rui.zhang@...el.com>
> 
> Current thermal code does not handle system sleep well because
> 1. the cooling device cooling state may be changed during suspend
> 2. the previous temperature reading becomes invalid after resumed because
>    it is got before system sleep
> 3. updating thermal zone device during suspending/resuming
>    is wrong because some devices may have already been suspended
>    or may have not been resumed.
> 
> Thus, the proper way to do this is to cancel all thermal zone
> device update requirements during suspend/resume, and after all
> the devices have been resumed, reset and update every registered
> thermal zone devices.
> 
> This also fixes a regression introduced by:
> Commit 19593a1fb1f6 ("ACPI / fan: convert to platform driver")
> Because, with above commit applied, all the fan devices are attached
> to the acpi_general_pm_domain, and they are turned on by the pm_domain
> automatically after resume, without the awareness of thermal core.
> 
> CC: <stable@...r.kernel.org> #3.18+
> Reference: https://bugzilla.kernel.org/show_bug.cgi?id=78201
> Reference: https://bugzilla.kernel.org/show_bug.cgi?id=91411
> Tested-by: Manuel Krause <manuelkrause@...scape.net>
> Tested-by: szegad <szegadlo@...zta.onet.pl>
> Tested-by: prash <prash.n.rao@...il.com>
> Tested-by: amish <ammdispose-arch@...oo.com>
> Tested-by: Matthias <morpheusxyz123@...oo.de>
> Reviewed-by: Javi Merino <javi.merino@....com>
> Signed-off-by: Zhang Rui <rui.zhang@...el.com>
> Signed-off-by: Chen Yu <yu.c.chen@...el.com>

Acked-by: Eduardo Valentin <edubezval@...il.com>


> ---
>  drivers/thermal/thermal_core.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 682bc1e..9aae767 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -37,6 +37,7 @@
>  #include <linux/of.h>
>  #include <net/netlink.h>
>  #include <net/genetlink.h>
> +#include <linux/suspend.h>
>  
>  #define CREATE_TRACE_POINTS
>  #include <trace/events/thermal.h>
> @@ -59,6 +60,8 @@ static LIST_HEAD(thermal_governor_list);
>  static DEFINE_MUTEX(thermal_list_lock);
>  static DEFINE_MUTEX(thermal_governor_lock);
>  
> +static atomic_t in_suspend;
> +
>  static struct thermal_governor *def_governor;
>  
>  static struct thermal_governor *__find_governor(const char *name)
> @@ -554,6 +557,9 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
>  {
>  	int count;
>  
> +	if (atomic_read(&in_suspend))
> +		return;
> +
>  	if (!tz->ops->get_temp)
>  		return;
>  
> @@ -2155,6 +2161,36 @@ static void thermal_unregister_governors(void)
>  	thermal_gov_power_allocator_unregister();
>  }
>  
> +static int thermal_pm_notify(struct notifier_block *nb,
> +				unsigned long mode, void *_unused)
> +{
> +	struct thermal_zone_device *tz;
> +
> +	switch (mode) {
> +	case PM_HIBERNATION_PREPARE:
> +	case PM_RESTORE_PREPARE:
> +	case PM_SUSPEND_PREPARE:
> +		atomic_set(&in_suspend, 1);
> +		break;
> +	case PM_POST_HIBERNATION:
> +	case PM_POST_RESTORE:
> +	case PM_POST_SUSPEND:
> +		atomic_set(&in_suspend, 0);
> +		list_for_each_entry(tz, &thermal_tz_list, node) {
> +			thermal_zone_device_reset(tz);
> +			thermal_zone_device_update(tz);
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +	return 0;
> +}
> +
> +static struct notifier_block thermal_pm_nb = {
> +	.notifier_call = thermal_pm_notify,
> +};
> +
>  static int __init thermal_init(void)
>  {
>  	int result;
> @@ -2175,6 +2211,11 @@ static int __init thermal_init(void)
>  	if (result)
>  		goto exit_netlink;
>  
> +	result = register_pm_notifier(&thermal_pm_nb);
> +	if (result)
> +		pr_warn("Thermal: Can not register suspend notifier, return %d\n",
> +			result);
> +
>  	return 0;
>  
>  exit_netlink:
> @@ -2194,6 +2235,7 @@ error:
>  
>  static void __exit thermal_exit(void)
>  {
> +	unregister_pm_notifier(&thermal_pm_nb);
>  	of_thermal_destroy_zones();
>  	genetlink_exit();
>  	class_unregister(&thermal_class);
> -- 
> 1.8.4.2
> 
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