1 files changed, 40 insertions, 1 deletions

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 0d7116f34b95..130f513e08c9 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -35,6 +35,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
+#include <linux/delay.h>
 #include <asm/unaligned.h>
 
 #ifdef CONFIG_ACPI_PROCFS_POWER
@@ -534,6 +535,20 @@ static int acpi_battery_get_state(struct acpi_battery *battery)
                         " invalid.\n");
         }
 
+        /*
+         * When fully charged, some batteries wrongly report
+         * capacity_now = design_capacity instead of = full_charge_capacity
+         */
+        if (battery->capacity_now > battery->full_charge_capacity
+            && battery->full_charge_capacity != ACPI_BATTERY_VALUE_UNKNOWN) {
+                battery->capacity_now = battery->full_charge_capacity;
+                if (battery->capacity_now != battery->design_capacity)
+                        printk_once(KERN_WARNING FW_BUG
+                                "battery: reported current charge level (%d) "
+                                "is higher than reported maximum charge level (%d).\n",
+                                battery->capacity_now, battery->full_charge_capacity);
+        }
+
         if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags)
             && battery->capacity_now >= 0 && battery->capacity_now <= 100)
                 battery->capacity_now = (battery->capacity_now *
@@ -1151,6 +1166,28 @@ static struct dmi_system_id bat_dmi_table[] = {
         {},
 };
 
+/*
+ * Some machines'(E,G Lenovo Z480) ECs are not stable
+ * during boot up and this causes battery driver fails to be
+ * probed due to failure of getting battery information
+ * from EC sometimes. After several retries, the operation
+ * may work. So add retry code here and 20ms sleep between
+ * every retries.
+ */
+static int acpi_battery_update_retry(struct acpi_battery *battery)
+{
+        int retry, ret;
+
+        for (retry = 5; retry; retry--) {
+                ret = acpi_battery_update(battery, false);
+                if (!ret)
+                        break;
+
+                msleep(20);
+        }
+        return ret;
+}
+
 static int acpi_battery_add(struct acpi_device *device)
 {
         int result = 0;
@@ -1169,9 +1206,11 @@ static int acpi_battery_add(struct acpi_device *device)
         mutex_init(&battery->sysfs_lock);
         if (acpi_has_method(battery->device->handle, "_BIX"))
                 set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);
-        result = acpi_battery_update(battery, false);
+
+        result = acpi_battery_update_retry(battery);
         if (result)
                 goto fail;
+
 #ifdef CONFIG_ACPI_PROCFS_POWER
         result = acpi_battery_add_fs(device);
 #endif