ACPI / battery: Add quirk for Asus GL502VSK and UX305LA

On Asus GL502VSK and UX305LA, ACPI incorrectly reports discharging when
battery is full and AC is plugged.

However rate_now is correct under this circumstance, hence we can use
"rate_now == 0" as a predicate to report battery full status correctly.

Link: https://bugs.launchpad.net/bugs/1482390
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/battery.c

@@ -70,6 +70,7 @@ static async_cookie_t async_cookie;
 static bool battery_driver_registered;
 static int battery_bix_broken_package;
 static int battery_notification_delay_ms;
+static int battery_full_discharging;
 static unsigned int cache_time = 1000;
 module_param(cache_time, uint, 0644);
 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
@@ -214,9 +215,12 @@ static int acpi_battery_get_property(struct power_supply *psy,
 		return -ENODEV;
 	switch (psp) {
 	case POWER_SUPPLY_PROP_STATUS:
-		if (battery->state & ACPI_BATTERY_STATE_DISCHARGING)
-			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
-		else if (battery->state & ACPI_BATTERY_STATE_CHARGING)
+		if (battery->state & ACPI_BATTERY_STATE_DISCHARGING) {
+			if (battery_full_discharging && battery->rate_now == 0)
+				val->intval = POWER_SUPPLY_STATUS_FULL;
+			else
+				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		} else if (battery->state & ACPI_BATTERY_STATE_CHARGING)
 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
 		else if (acpi_battery_is_charged(battery))
 			val->intval = POWER_SUPPLY_STATUS_FULL;
@@ -1166,6 +1170,12 @@ battery_notification_delay_quirk(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int __init battery_full_discharging_quirk(const struct dmi_system_id *d)
+{
+	battery_full_discharging = 1;
+	return 0;
+}
+
 static const struct dmi_system_id bat_dmi_table[] __initconst = {
 	{
 		.callback = battery_bix_broken_package_quirk,
@@ -1183,6 +1193,22 @@ static const struct dmi_system_id bat_dmi_table[] __initconst = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire V5-573G"),
 		},
 	},
+	{
+		.callback = battery_full_discharging_quirk,
+		.ident = "ASUS GL502VSK",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "GL502VSK"),
+		},
+	},
+	{
+		.callback = battery_full_discharging_quirk,
+		.ident = "ASUS UX305LA",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "UX305LA"),
+		},
+	},
 	{},
 };