Re: [PATCH] ACPI / sleep: Drain outstanding events after disabling multiple GPEs

2014-11-14 Thread Rafael J. Wysocki
On Saturday, November 15, 2014 02:30:51 AM Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki 
> 
> After multiple GPEs have been disabled at the low level in one go,
> like when acpi_disable_all_gpes() is called, we should always drain
> all of the outstanding events from them, or the ACPICA's GPE handling
> code may re-enable one of them as a result of a race condition.

Scratch the last part.

We simply need to drain them to prevent the GPE handling code from
being executed in parallel with whatever happens after the GPEs have
been disabled.

> For this reason, call acpi_os_wait_events_complete() after
> acpi_enable_all_wakeup_gpes() and acpi_disable_all_gpes() in
> acpi_freeze_prepare() and acpi_power_off_prepare(), respectively.
> 
> Signed-off-by: Rafael J. Wysocki 
> ---
>  drivers/acpi/sleep.c |2 ++
>  1 file changed, 2 insertions(+)
> 
> Index: linux-pm/drivers/acpi/sleep.c
> ===
> --- linux-pm.orig/drivers/acpi/sleep.c
> +++ linux-pm/drivers/acpi/sleep.c
> @@ -630,6 +630,7 @@ static int acpi_freeze_begin(void)
>  static int acpi_freeze_prepare(void)
>  {
>   acpi_enable_all_wakeup_gpes();
> + acpi_os_wait_events_complete();
>   enable_irq_wake(acpi_gbl_FADT.sci_interrupt);
>   return 0;
>  }
> @@ -825,6 +826,7 @@ static void acpi_power_off_prepare(void)
>   /* Prepare to power off the system */
>   acpi_sleep_prepare(ACPI_STATE_S5);
>   acpi_disable_all_gpes();
> + acpi_os_wait_events_complete();
>  }
>  
>  static void acpi_power_off(void)
> 
> --
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-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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Re: [PATCH] ACPI / sleep: Drain outstanding events after disabling multiple GPEs

2014-11-14 Thread Rafael J. Wysocki
On Saturday, November 15, 2014 02:30:51 AM Rafael J. Wysocki wrote:
 From: Rafael J. Wysocki rafael.j.wyso...@intel.com
 
 After multiple GPEs have been disabled at the low level in one go,
 like when acpi_disable_all_gpes() is called, we should always drain
 all of the outstanding events from them, or the ACPICA's GPE handling
 code may re-enable one of them as a result of a race condition.

Scratch the last part.

We simply need to drain them to prevent the GPE handling code from
being executed in parallel with whatever happens after the GPEs have
been disabled.

 For this reason, call acpi_os_wait_events_complete() after
 acpi_enable_all_wakeup_gpes() and acpi_disable_all_gpes() in
 acpi_freeze_prepare() and acpi_power_off_prepare(), respectively.
 
 Signed-off-by: Rafael J. Wysocki rafael.j.wyso...@intel.com
 ---
  drivers/acpi/sleep.c |2 ++
  1 file changed, 2 insertions(+)
 
 Index: linux-pm/drivers/acpi/sleep.c
 ===
 --- linux-pm.orig/drivers/acpi/sleep.c
 +++ linux-pm/drivers/acpi/sleep.c
 @@ -630,6 +630,7 @@ static int acpi_freeze_begin(void)
  static int acpi_freeze_prepare(void)
  {
   acpi_enable_all_wakeup_gpes();
 + acpi_os_wait_events_complete();
   enable_irq_wake(acpi_gbl_FADT.sci_interrupt);
   return 0;
  }
 @@ -825,6 +826,7 @@ static void acpi_power_off_prepare(void)
   /* Prepare to power off the system */
   acpi_sleep_prepare(ACPI_STATE_S5);
   acpi_disable_all_gpes();
 + acpi_os_wait_events_complete();
  }
  
  static void acpi_power_off(void)
 
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-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/