Re: Help me fix a regression caused by 56b9918490 (PM: sleep: Simplify suspend-to-idle control flow)

["Kenneth R. Crudup" <kenny@panix.com>]

On Tue, 26 Nov 2019, Rafael J. Wysocki wrote:

> OK, so just to double check if I understand you correctly, you are
> running the Linus' tip with [the patch] on top and with two extra
> WARN_ON(1) statements in acpi_ec_query_flushed()?

Yeah:

----
$ git diff lk-linus/master drivers/acpi/

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index da1e5c5ce150..0bb13a596e4f 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -530,9 +530,11 @@ static bool acpi_ec_query_flushed(struct acpi_ec *ec)
 	bool flushed;
 	unsigned long flags;

+	WARN_ON(1);
 	spin_lock_irqsave(&ec->lock, flags);
 	flushed = !ec->nr_pending_queries;
 	spin_unlock_irqrestore(&ec->lock, flags);
+	WARN_ON(1);
 	return flushed;
 }

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 2af937a8b1c5..003b314eda29 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -977,6 +977,13 @@ static int acpi_s2idle_prepare_late(void)
 	return 0;
 }

+static void acpi_s2idle_sync(void)
+{
+	acpi_os_wait_events_complete(); /* synchronize GPE processing */
+	acpi_ec_flush_work();
+	acpi_os_wait_events_complete(); /* synchronize Notify handling */
+}
+
 static void acpi_s2idle_wake(void)
 {
 	/*
@@ -1005,9 +1012,7 @@ static void acpi_s2idle_wake(void)
 		 * The EC driver uses the system workqueue and an additional
 		 * special one, so those need to be flushed too.
 		 */
-		acpi_os_wait_events_complete(); /* synchronize EC GPE processing */
-		acpi_ec_flush_work();
-		acpi_os_wait_events_complete(); /* synchronize Notify handling */
+		acpi_s2idle_sync();

 		rearm_wake_irq(acpi_sci_irq);
 	}
@@ -1024,6 +1029,8 @@ static void acpi_s2idle_restore_early(void)

 static void acpi_s2idle_restore(void)
 {
+	acpi_s2idle_sync();
+
 	s2idle_wakeup = false;

 	acpi_enable_all_runtime_gpes();
----

	-Kenny

-- 
Kenneth R. Crudup  Sr. SW Engineer, Scott County Consulting, Silicon Valley