ACK: [PATCH 1/1][SRU][Impish] PM: s2idle: ACPI: Fix wakeup interrupts handling
Stefan Bader
stefan.bader at canonical.com
Tue Mar 15 08:20:27 UTC 2022
On 24.02.22 08:02, You-Sheng Yang wrote:
> From: "Rafael J. Wysocki" <rafael.j.wysocki at intel.com>
>
> BugLink: https://bugs.launchpad.net/bugs/1961739
>
> After commit e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race
> related to the EC GPE") wakeup interrupts occurring immediately after
> the one discarded by acpi_s2idle_wake() may be missed. Moreover, if
> the SCI triggers again immediately after the rearming in
> acpi_s2idle_wake(), that wakeup may be missed too.
>
> The problem is that pm_system_irq_wakeup() only calls pm_system_wakeup()
> when pm_wakeup_irq is 0, but that's not the case any more after the
> interrupt causing acpi_s2idle_wake() to run until pm_wakeup_irq is
> cleared by the pm_wakeup_clear() call in s2idle_loop(). However,
> there may be wakeup interrupts occurring in that time frame and if
> that happens, they will be missed.
>
> To address that issue first move the clearing of pm_wakeup_irq to
> the point at which it is known that the interrupt causing
> acpi_s2idle_wake() to tun will be discarded, before rearming the SCI
> for wakeup. Moreover, because that only reduces the size of the
> time window in which the issue may manifest itself, allow
> pm_system_irq_wakeup() to register two second wakeup interrupts in
> a row and, when discarding the first one, replace it with the second
> one. [Of course, this assumes that only one wakeup interrupt can be
> discarded in one go, but currently that is the case and I am not
> aware of any plans to change that.]
>
> Fixes: e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race related to the EC GPE")
> Cc: 5.4+ <stable at vger.kernel.org> # 5.4+
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
> (cherry picked from commit cb1f65c1e1424a4b5e4a86da8aa3b8fd8459c8ec)
> Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
> drivers/acpi/sleep.c | 1 +
> drivers/base/power/wakeup.c | 41 ++++++++++++++++++++++++++++++-------
> include/linux/suspend.h | 4 ++--
> kernel/power/main.c | 5 ++++-
> kernel/power/process.c | 2 +-
> kernel/power/suspend.c | 2 --
> 6 files changed, 42 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
> index 3023224515ab..7ae09e4b4592 100644
> --- a/drivers/acpi/sleep.c
> +++ b/drivers/acpi/sleep.c
> @@ -767,6 +767,7 @@ bool acpi_s2idle_wake(void)
> return true;
> }
>
> + pm_wakeup_clear(acpi_sci_irq);
> rearm_wake_irq(acpi_sci_irq);
> }
>
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index 99bda0da23a8..8666590201c9 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -34,7 +34,8 @@ suspend_state_t pm_suspend_target_state;
> bool events_check_enabled __read_mostly;
>
> /* First wakeup IRQ seen by the kernel in the last cycle. */
> -unsigned int pm_wakeup_irq __read_mostly;
> +static unsigned int wakeup_irq[2] __read_mostly;
> +static DEFINE_RAW_SPINLOCK(wakeup_irq_lock);
>
> /* If greater than 0 and the system is suspending, terminate the suspend. */
> static atomic_t pm_abort_suspend __read_mostly;
> @@ -942,19 +943,45 @@ void pm_system_cancel_wakeup(void)
> atomic_dec_if_positive(&pm_abort_suspend);
> }
>
> -void pm_wakeup_clear(bool reset)
> +void pm_wakeup_clear(unsigned int irq_number)
> {
> - pm_wakeup_irq = 0;
> - if (reset)
> + raw_spin_lock_irq(&wakeup_irq_lock);
> +
> + if (irq_number && wakeup_irq[0] == irq_number)
> + wakeup_irq[0] = wakeup_irq[1];
> + else
> + wakeup_irq[0] = 0;
> +
> + wakeup_irq[1] = 0;
> +
> + raw_spin_unlock_irq(&wakeup_irq_lock);
> +
> + if (!irq_number)
> atomic_set(&pm_abort_suspend, 0);
> }
>
> void pm_system_irq_wakeup(unsigned int irq_number)
> {
> - if (pm_wakeup_irq == 0) {
> - pm_wakeup_irq = irq_number;
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&wakeup_irq_lock, flags);
> +
> + if (wakeup_irq[0] == 0)
> + wakeup_irq[0] = irq_number;
> + else if (wakeup_irq[1] == 0)
> + wakeup_irq[1] = irq_number;
> + else
> + irq_number = 0;
> +
> + raw_spin_unlock_irqrestore(&wakeup_irq_lock, flags);
> +
> + if (irq_number)
> pm_system_wakeup();
> - }
> +}
> +
> +unsigned int pm_wakeup_irq(void)
> +{
> + return wakeup_irq[0];
> }
>
> /**
> diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> index 8af13ba60c7e..7709998e3244 100644
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -505,14 +505,14 @@ extern void ksys_sync_helper(void);
>
> /* drivers/base/power/wakeup.c */
> extern bool events_check_enabled;
> -extern unsigned int pm_wakeup_irq;
> extern suspend_state_t pm_suspend_target_state;
>
> extern bool pm_wakeup_pending(void);
> extern void pm_system_wakeup(void);
> extern void pm_system_cancel_wakeup(void);
> -extern void pm_wakeup_clear(bool reset);
> +extern void pm_wakeup_clear(unsigned int irq_number);
> extern void pm_system_irq_wakeup(unsigned int irq_number);
> +extern unsigned int pm_wakeup_irq(void);
> extern bool pm_get_wakeup_count(unsigned int *count, bool block);
> extern bool pm_save_wakeup_count(unsigned int count);
> extern void pm_wakep_autosleep_enabled(bool set);
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 44169f3081fd..7e646079fbeb 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -504,7 +504,10 @@ static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
> struct kobj_attribute *attr,
> char *buf)
> {
> - return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
> + if (!pm_wakeup_irq())
> + return -ENODATA;
> +
> + return sprintf(buf, "%u\n", pm_wakeup_irq());
> }
>
> power_attr_ro(pm_wakeup_irq);
> diff --git a/kernel/power/process.c b/kernel/power/process.c
> index 37401c99b7d7..ee78a39463e6 100644
> --- a/kernel/power/process.c
> +++ b/kernel/power/process.c
> @@ -134,7 +134,7 @@ int freeze_processes(void)
> if (!pm_freezing)
> atomic_inc(&system_freezing_cnt);
>
> - pm_wakeup_clear(true);
> + pm_wakeup_clear(0);
> pr_info("Freezing user space processes ... ");
> pm_freezing = true;
> error = try_to_freeze_tasks(true);
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index eb75f394a059..13d905dd3267 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -138,8 +138,6 @@ static void s2idle_loop(void)
> break;
> }
>
> - pm_wakeup_clear(false);
> -
> s2idle_enter();
> }
>
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