Input: i8042 - enable keyboard wakeups by default when s2idle is used

Previously, on typical consumer laptops, pressing a key on the keyboard
when the system is in suspend would cause it to wake up (default or
unconditional behaviour). This happens because the EC generates a SCI
interrupt in this scenario.

That is no longer true on modern laptops based on Intel WhiskeyLake,
including Acer Swift SF314-55G, Asus UX333FA, Asus UX433FN and Asus
UX533FD. We confirmed with Asus EC engineers that the "Modern Standby"
design has been modified so that the EC no longer generates a SCI
in this case; the keyboard controller itself should be used for wakeup.

In order to retain the standard behaviour of being able to use the
keyboard to wake up the system, enable serio wakeups by default on
platforms that are using s2idle.

Link: https://lkml.kernel.org/r/CAB4CAwfQ0mPMqCLp95TVjw4J0r5zKPWkSvvkK4cpZUGE--w8bQ@mail.gmail.com
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/serio/i8042.c

@@ -1395,15 +1395,26 @@ static void __init i8042_register_ports(void)
 	for (i = 0; i < I8042_NUM_PORTS; i++) {
 		struct serio *serio = i8042_ports[i].serio;
 
-		if (serio) {
-			printk(KERN_INFO "serio: %s at %#lx,%#lx irq %d\n",
-				serio->name,
-				(unsigned long) I8042_DATA_REG,
-				(unsigned long) I8042_COMMAND_REG,
-				i8042_ports[i].irq);
-			serio_register_port(serio);
-			device_set_wakeup_capable(&serio->dev, true);
-		}
+		if (!serio)
+			continue;
+
+		printk(KERN_INFO "serio: %s at %#lx,%#lx irq %d\n",
+			serio->name,
+			(unsigned long) I8042_DATA_REG,
+			(unsigned long) I8042_COMMAND_REG,
+			i8042_ports[i].irq);
+		serio_register_port(serio);
+		device_set_wakeup_capable(&serio->dev, true);
+
+		/*
+		 * On platforms using suspend-to-idle, allow the keyboard to
+		 * wake up the system from sleep by enabling keyboard wakeups
+		 * by default.  This is consistent with keyboard wakeup
+		 * behavior on many platforms using suspend-to-RAM (ACPI S3)
+		 * by default.
+		 */
+		if (pm_suspend_via_s2idle() && i == I8042_KBD_PORT_NO)
+			device_set_wakeup_enable(&serio->dev, true);
 	}
 }
 

include/linux/suspend.h

@@ -251,6 +251,7 @@ static inline bool idle_should_enter_s2idle(void)
 	return unlikely(s2idle_state == S2IDLE_STATE_ENTER);
 }
 
+extern bool pm_suspend_via_s2idle(void);
 extern void __init pm_states_init(void);
 extern void s2idle_set_ops(const struct platform_s2idle_ops *ops);
 extern void s2idle_wake(void);
@@ -282,6 +283,7 @@ static inline void pm_set_suspend_via_firmware(void) {}
 static inline void pm_set_resume_via_firmware(void) {}
 static inline bool pm_suspend_via_firmware(void) { return false; }
 static inline bool pm_resume_via_firmware(void) { return false; }
+static inline bool pm_suspend_via_s2idle(void) { return false; }
 
 static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
 static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }

kernel/power/suspend.c

@@ -62,6 +62,12 @@ static DECLARE_WAIT_QUEUE_HEAD(s2idle_wait_head);
 enum s2idle_states __read_mostly s2idle_state;
 static DEFINE_SPINLOCK(s2idle_lock);
 
+bool pm_suspend_via_s2idle(void)
+{
+	return mem_sleep_current == PM_SUSPEND_TO_IDLE;
+}
+EXPORT_SYMBOL_GPL(pm_suspend_via_s2idle);
+
 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
 {
 	lock_system_sleep();