linux-kernel - Re: [PATCH 3/5] thermal: x86_pkg_temp: Handle the FROZEN hot plug notifier actions.

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Date:	Sat, 14 May 2016 00:59:13 +0000
From:	"Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>
To:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"rcochran@...utronix.de" <rcochran@...utronix.de>
CC:	"Zhang, Rui" <rui.zhang@...el.com>,
	"edubezval@...il.com" <edubezval@...il.com>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"rt@...utronix.de" <rt@...utronix.de>
Subject: Re: [PATCH 3/5] thermal: x86_pkg_temp: Handle the FROZEN hot plug
 notifier actions.

On Fri, 2016-03-18 at 22:26 +0100, Richard Cochran wrote:
> When performing a suspend operation, the kernel brings all of the
> non-boot CPUs offline, calling the hot plug notifiers with the flag,
> CPU_TASKS_FROZEN, set in the action code.  Similarly, during resume,
> the CPUs are brought back online, but again the notifiers have the
> FROZEN flag set.
> 
> While some very few drivers really need to treat suspend/resume
> specially, this driver unintentionally ignores the notifications.
> 
> This patch changes the driver to cancel its work item when the CPU
> goes down, even during a suspend operation.  As a result, the
> suspended state is no longer a special case.
> 
> Cc: Zhang Rui <rui.zhang@...el.com>
> Cc: Eduardo Valentin <edubezval@...il.com>
> Cc: linux-pm@...r.kernel.org
> Signed-off-by: Richard Cochran <rcochran@...utronix.de>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>

> ---
>  drivers/thermal/x86_pkg_temp_thermal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/x86_pkg_temp_thermal.c
> b/drivers/thermal/x86_pkg_temp_thermal.c
> index 7fc919f..97f0a2b 100644
> --- a/drivers/thermal/x86_pkg_temp_thermal.c
> +++ b/drivers/thermal/x86_pkg_temp_thermal.c
> @@ -555,7 +555,7 @@ static int pkg_temp_thermal_cpu_callback(struct
> notifier_block *nfb,
>  {
>  	unsigned int cpu = (unsigned long) hcpu;
>  
> -	switch (action) {
> +	switch (action & ~CPU_TASKS_FROZEN) {
>  	case CPU_ONLINE:
>  	case CPU_DOWN_FAILED:
>  		get_core_online(cpu);