ACPI / EC / PM: Close race between EC and resume from hibernation
There is a race between resume from hibernation and the EC driver
that may result in restoring the hibernation image in the middle of
an EC transaction in progress, which in turn may lead to
unpredictable behavior of the platform.
To remove that race condition, add a helpers for suspending and
resuming EC transactions in a safe way to be executed by the ACPI
platform hibernate pre-restore and restore cleanup callbacks.
http://bugzilla.kernel.org/show_bug.cgi?id=14668
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 79d33d9..f01f8e8 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -552,8 +552,17 @@
hibernate_nvs_restore();
}
-static void acpi_pm_enable_gpes(void)
+static int acpi_pm_pre_restore(void)
{
+ acpi_disable_all_gpes();
+ acpi_os_wait_events_complete(NULL);
+ acpi_ec_suspend_transactions();
+ return 0;
+}
+
+static void acpi_pm_restore_cleanup(void)
+{
+ acpi_ec_resume_transactions();
acpi_enable_all_runtime_gpes();
}
@@ -565,8 +574,8 @@
.prepare = acpi_pm_prepare,
.enter = acpi_hibernation_enter,
.leave = acpi_hibernation_leave,
- .pre_restore = acpi_pm_disable_gpes,
- .restore_cleanup = acpi_pm_enable_gpes,
+ .pre_restore = acpi_pm_pre_restore,
+ .restore_cleanup = acpi_pm_restore_cleanup,
};
/**
@@ -618,8 +627,8 @@
.prepare = acpi_pm_disable_gpes,
.enter = acpi_hibernation_enter,
.leave = acpi_hibernation_leave,
- .pre_restore = acpi_pm_disable_gpes,
- .restore_cleanup = acpi_pm_enable_gpes,
+ .pre_restore = acpi_pm_pre_restore,
+ .restore_cleanup = acpi_pm_restore_cleanup,
.recover = acpi_pm_finish,
};
#endif /* CONFIG_HIBERNATION */