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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-02-04 18:35:22 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-02-07 21:02:31 +0100
commitcb1f65c1e1424a4b5e4a86da8aa3b8fd8459c8ec (patch)
tree24fb6cf5301f57a5346c375ae5f5b3cbcc0304ee /kernel
parentdc0075ba7f387fe4c48a8c674b11ab6f374a6acc (diff)
PM: s2idle: ACPI: Fix wakeup interrupts handling
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@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/power/main.c5
-rw-r--r--kernel/power/process.c2
-rw-r--r--kernel/power/suspend.c2
3 files changed, 5 insertions, 4 deletions
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 b7e7798637b8..11b570fcf049 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 80cc1f0f502b..6fcdee7e87a5 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -136,8 +136,6 @@ static void s2idle_loop(void)
break;
}
- pm_wakeup_clear(false);
-
s2idle_enter();
}