[PATCH] ACPI / LPSS: Avoid PM quirks on suspend and resume from S3

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It is reported that commit a192aa923b66a (ACPI / LPSS: Consolidate
runtime PM and system sleep handling) introduced a system suspend
regression on some machines, but the only functional change made by
it was to cause the PM quirks in the LPSS to also be used during
system suspend and resume.  While that should always work for
suspend-to-idle, it turns out to be problematic for S3
(suspend-to-RAM).

To address that issue restore the previous S3 suspend and resume
behavior of the LPSS to avoid applying PM quirks then.

Fixes: a192aa923b66a (ACPI / LPSS: Consolidate runtime PM and system sleep handling)
Link: https://bugs.launchpad.net/bugs/1774950
Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpi_lpss.c |   18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

Index: linux-pm/drivers/acpi/acpi_lpss.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpi_lpss.c
+++ linux-pm/drivers/acpi/acpi_lpss.c
@@ -22,6 +22,7 @@
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/pwm.h>
+#include <linux/suspend.h>
 #include <linux/delay.h>
 
 #include "internal.h"
@@ -940,9 +941,10 @@ static void lpss_iosf_exit_d3_state(void
 	mutex_unlock(&lpss_iosf_mutex);
 }
 
-static int acpi_lpss_suspend(struct device *dev, bool wakeup)
+static int acpi_lpss_suspend(struct device *dev, bool runtime)
 {
 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+	bool wakeup = runtime || device_may_wakeup(dev);
 	int ret;
 
 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
@@ -955,13 +957,14 @@ static int acpi_lpss_suspend(struct devi
 	 * wrong status for devices being about to be powered off. See
 	 * lpss_iosf_enter_d3_state() for further information.
 	 */
-	if (lpss_quirks & LPSS_QUIRK_ALWAYS_POWER_ON && iosf_mbi_available())
+	if ((runtime || !pm_suspend_via_firmware()) &&
+	    lpss_quirks & LPSS_QUIRK_ALWAYS_POWER_ON && iosf_mbi_available())
 		lpss_iosf_enter_d3_state();
 
 	return ret;
 }
 
-static int acpi_lpss_resume(struct device *dev)
+static int acpi_lpss_resume(struct device *dev, bool runtime)
 {
 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
 	int ret;
@@ -970,7 +973,8 @@ static int acpi_lpss_resume(struct devic
 	 * This call is kept first to be in symmetry with
 	 * acpi_lpss_runtime_suspend() one.
 	 */
-	if (lpss_quirks & LPSS_QUIRK_ALWAYS_POWER_ON && iosf_mbi_available())
+	if ((runtime || !pm_resume_via_firmware()) &&
+	    lpss_quirks & LPSS_QUIRK_ALWAYS_POWER_ON && iosf_mbi_available())
 		lpss_iosf_exit_d3_state();
 
 	ret = acpi_dev_resume(dev);
@@ -994,12 +998,12 @@ static int acpi_lpss_suspend_late(struct
 		return 0;
 
 	ret = pm_generic_suspend_late(dev);
-	return ret ? ret : acpi_lpss_suspend(dev, device_may_wakeup(dev));
+	return ret ? ret : acpi_lpss_suspend(dev, false);
 }
 
 static int acpi_lpss_resume_early(struct device *dev)
 {
-	int ret = acpi_lpss_resume(dev);
+	int ret = acpi_lpss_resume(dev, false);
 
 	return ret ? ret : pm_generic_resume_early(dev);
 }
@@ -1014,7 +1018,7 @@ static int acpi_lpss_runtime_suspend(str
 
 static int acpi_lpss_runtime_resume(struct device *dev)
 {
-	int ret = acpi_lpss_resume(dev);
+	int ret = acpi_lpss_resume(dev, true);
 
 	return ret ? ret : pm_generic_runtime_resume(dev);
 }