ACPI / EC: Restore polling during noirq suspend/resume phases

[ Upstream commit 3cd091a7 ]

Commit 66259146 (ACPI / EC: Drop EC noirq hooks to fix a
regression) modified the ACPI EC driver so that it doesn't switch
over to busy polling mode during noirq stages of system suspend and
resume in an attempt to fix an issue resulting from that behavior.

However, that modification introduced a system resume regression on
Thinkpad X240, so make the EC driver switch over to the polling mode
during noirq stages of system suspend and resume again, which
effectively reverts the problematic commit.

Fixes: 66259146 (ACPI / EC: Drop EC noirq hooks to fix a regression)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197863Reported-by: Markus Demleitner <m@tfiu.de>
Tested-by: Markus Demleitner <m@tfiu.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/acpi/ec.c

@@ -1927,6 +1927,9 @@ static int acpi_ec_suspend_noirq(struct device *dev)
 	    ec->reference_count >= 1)
 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 
+	if (acpi_sleep_no_ec_events())
+		acpi_ec_enter_noirq(ec);
+
 	return 0;
 }
 
@@ -1934,6 +1937,9 @@ static int acpi_ec_resume_noirq(struct device *dev)
 {
 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
 
+	if (acpi_sleep_no_ec_events())
+		acpi_ec_leave_noirq(ec);
+
 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 	    ec->reference_count >= 1)
 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);