ACPI / EC: Use ec_no_wakeup on Thinkpad X1 Carbon 6th

On this system EC interrupt triggers constantly kicking devices out of
low power states and thus blocking power management. The system also has
a PCIe root port hosting Alpine Ridge Thunderbolt controller and it
never gets a chance to go to D3cold because of this.

Since the power button works the same regardless if EC interrupt is
enabled or not during s2idle, add a quirk for this machine that sets
ec_no_wakeup=true preventing spurious wakeups.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/ec.c

@@ -2037,6 +2037,17 @@ static inline void acpi_ec_query_exit(void)
 	}
 }
 
+static const struct dmi_system_id acpi_ec_no_wakeup[] = {
+	{
+		.ident = "Thinkpad X1 Carbon 6th",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "20KGS3JF01"),
+		},
+	},
+	{ },
+};
+
 int __init acpi_ec_init(void)
 {
 	int result;
@@ -2047,6 +2058,15 @@ int __init acpi_ec_init(void)
 	if (result)
 		return result;
 
+	/*
+	 * Disable EC wakeup on following systems to prevent periodic
+	 * wakeup from EC GPE.
+	 */
+	if (dmi_check_system(acpi_ec_no_wakeup)) {
+		ec_no_wakeup = true;
+		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
+	}
+
 	/* Drivers must be started after acpi_ec_query_init() */
 	dsdt_fail = acpi_bus_register_driver(&acpi_ec_driver);
 	/*