提交 cb1f65c1 编写于 作者: R Rafael J. Wysocki

PM: s2idle: ACPI: Fix wakeup interrupts handling

After commit e3728b50 ("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: e3728b50 ("ACPI: PM: s2idle: Avoid possible race related to the EC GPE")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
上级 dc0075ba
......@@ -758,6 +758,7 @@ bool acpi_s2idle_wake(void)
return true;
}
pm_wakeup_clear(acpi_sci_irq);
rearm_wake_irq(acpi_sci_irq);
}
......
......@@ -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];
}
/**
......
......@@ -497,14 +497,14 @@ 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);
......
......@@ -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);
......
......@@ -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);
......
......@@ -136,8 +136,6 @@ static void s2idle_loop(void)
break;
}
pm_wakeup_clear(false);
s2idle_enter();
}
......
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