linux-kernel - Re: [PATCH][RFC] ACPI / PM: Fix incorrect wakeup irq setting before suspend-to-idle

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Date:	Fri, 25 Sep 2015 03:23:48 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Chen Yu <yu.c.chen@...el.com>
Cc:	rafael.j.wysocki@...el.com, jiang.liu@...ux.intel.com,
	rui.zhang@...el.com, len.brown@...el.com,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH][RFC] ACPI / PM: Fix incorrect wakeup irq setting before suspend-to-idle

On Monday, August 10, 2015 10:11:26 AM Chen Yu wrote:
> For ACPI compatible system, SCI(ACPI System Control
> Interrupt) is used to wake system up from suspend-to-idle.
> Once CPU is woken up by SCI, interrupt handler will
> firstly checks if current interrupt is legal to wake up
> the whole system, thus irq_pm_check_wakeup is invoked
> to validate the irq number. However, before suspend-to-idle,
> acpi_gbl_FADT.sci_interrupt is marked rather than actual
> irq number in acpi_freeze_prepare, this might lead to unable
> to wake up the system.
> 
> This patch fixes this problem by marking the irq number
> return by acpi_gsi_to_irq as IRQD_WAKEUP_STATE, rather than
> marking the acpi_gbl_FADT.sci_interrupt.
> 
> Signed-off-by: Chen Yu <yu.c.chen@...el.com>

That would only really matter if GPE devices were used, but I've never seen
a system using them in practice, so this is more of a theoretical issue.

> ---
>  drivers/acpi/osl.c   |  5 ++++-
>  drivers/acpi/sleep.c | 20 ++++++++++++++++++--
>  drivers/acpi/sleep.h |  5 +++++
>  3 files changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 3b8963f..8e1420a 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -49,6 +49,7 @@
>  #include <asm/uaccess.h>
>  
>  #include "internal.h"
> +#include "sleep.h"
>  
>  #define _COMPONENT		ACPI_OS_SERVICES
>  ACPI_MODULE_NAME("osl");
> @@ -850,7 +851,9 @@ acpi_os_install_interrupt_handler(u32 gsi, acpi_osd_handler handler,
>  		       gsi);
>  		return AE_OK;
>  	}
> -
> +#ifdef CONFIG_SUSPEND
> +	set_wake_irq_freeze(irq);
> +#endif

Please don't use #ifdefs in function bodies.  You can use IS_ENABLED() for that.

>  	acpi_irq_handler = handler;
>  	acpi_irq_context = context;
>  	if (request_irq(irq, acpi_irq, IRQF_SHARED, "acpi", acpi_irq)) {
> diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
> index 2f0d4db..9e7b54e 100644
> --- a/drivers/acpi/sleep.c
> +++ b/drivers/acpi/sleep.c
> @@ -620,6 +620,22 @@ static const struct platform_suspend_ops acpi_suspend_ops_old = {
>  	.end = acpi_pm_end,
>  	.recover = acpi_pm_finish,
>  };
> +static int wake_irq_freeze = -EINVAL;

There may be more than one of these in theory.

> +
> +int get_wake_irq_freeze(void)
> +{
> +	if (IS_ERR_VALUE(wake_irq_freeze))
> +		return acpi_gbl_FADT.sci_interrupt;
> +	else
> +		return wake_irq_freeze;

That would look better this way IMO:

	return IS_ERR_VALUE(wake_irq_freeze) ?
		acpi_gbl_FADT.sci_interrupt : wake_irq_freeze;

> +}
> +EXPORT_SYMBOL_GPL(get_wake_irq_freeze);
> +
> +void set_wake_irq_freeze(unsigned int irq)
> +{
> +	wake_irq_freeze = (int)irq;
> +}
> +EXPORT_SYMBOL_GPL(set_wake_irq_freeze);
>  
>  static int acpi_freeze_begin(void)
>  {
> @@ -632,14 +648,14 @@ static int acpi_freeze_prepare(void)
>  	acpi_enable_wakeup_devices(ACPI_STATE_S0);
>  	acpi_enable_all_wakeup_gpes();
>  	acpi_os_wait_events_complete();
> -	enable_irq_wake(acpi_gbl_FADT.sci_interrupt);
> +	enable_irq_wake(get_wake_irq_freeze());
>  	return 0;
>  }
>  
>  static void acpi_freeze_restore(void)
>  {
>  	acpi_disable_wakeup_devices(ACPI_STATE_S0);
> -	disable_irq_wake(acpi_gbl_FADT.sci_interrupt);
> +	disable_irq_wake(get_wake_irq_freeze());
>  	acpi_enable_all_runtime_gpes();
>  }
>  
> diff --git a/drivers/acpi/sleep.h b/drivers/acpi/sleep.h
> index c797ffa..eca4fda 100644
> --- a/drivers/acpi/sleep.h
> +++ b/drivers/acpi/sleep.h
> @@ -6,3 +6,8 @@ extern struct list_head acpi_wakeup_device_list;
>  extern struct mutex acpi_device_lock;
>  
>  extern void acpi_resume_power_resources(void);
> +
> +#ifdef CONFIG_SUSPEND
> +extern int get_wake_irq_freeze(void);
> +extern void set_wake_irq_freeze(unsigned int irq);
> +#endif

Is the #ifdef needed here at all?

Thanks,
Rafael

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