On quite a few devices the battery code in the ACPI tables is buggy and
first checks the charging status bits of the charger-IC, and if those
report not charging it will report discharging, without looking at the
presence of AC power or at the battery dis(charge) current from the
fuel-gauge.
This causes the wrong status to be reported for the battery in the
following quite common scenario:
1) Plug in charger while battery is say half full, battery starts
charging, charging state bits indicate: pre-charge or fast-charge,
ACPI reported battery status is ok
2) When fully charged charging state bits indicate: end-of-charge,
ACPI reported battery status is ok
3) unplug the charger, wait 1 minute, replug. Now the battery voltage is
still above the start-charging threshold, so the charger will not start
charging to avoid wrecking the battery by repeatedly recharging the last 1%
capacity. The charger IC charging state bits now are all 0 (not-charging)
and the broken ACPI code wrongly translate this to "discharging" and ends
up setting the ACPI_BATTERY_STATE_DISCHARGING bit in its state field.
Reporting this "not charging" state as discharging is confusing for users,
making the user think his adapter/power-brick is broken or not properly
plugged in.
This commit adds a helper for handling the ACPI_BATTERY_STATE_DISCHARGING
state. This helper checks if we're an AC and the current going out of the
battery is 0 and in that case reports a status of "not charging" to
userspace rather then "discharging".
This replaces commit c68f0676ef7d ("ACPI / battery: Add quirk for Asus
GL502VSK and UX305LA"), a previous fix for this which was reverted.
Cc: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v2:
-Report "not charging" rather then "full"
---
drivers/acpi/battery.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 1fc0feceafaf..3770ac09fd30 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -200,6 +200,19 @@ static int acpi_battery_is_charged(struct acpi_battery *battery)
return 0;
}
+static int acpi_battery_handle_discharging(struct acpi_battery *battery)
+{
+ /*
+ * Some devices wrongly report discharging if the battery's charge level
+ * was above the device's start charging threshold atm the AC adapter
+ * was plugged in and the device thus did not start a new charge cycle.
+ */
+ if (power_supply_is_system_supplied() && battery->rate_now == 0)
+ return POWER_SUPPLY_STATUS_NOT_CHARGING;
+
+ return POWER_SUPPLY_STATUS_DISCHARGING;
+}
+
static int acpi_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
@@ -215,7 +228,7 @@ static int acpi_battery_get_property(struct power_supply *psy,
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
if (battery->state & ACPI_BATTERY_STATE_DISCHARGING)
- val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+ val->intval = acpi_battery_handle_discharging(battery);
else if (battery->state & ACPI_BATTERY_STATE_CHARGING)
val->intval = POWER_SUPPLY_STATUS_CHARGING;
else if (acpi_battery_is_charged(battery))
--
2.17.0
--
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