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[4/5] ACPI / battery: Add handling for devices which wrongly report discharging state

Message ID 20190202153757.26990-5-kai.heng.feng@canonical.com
State New
Headers show
Series [1/5] Revert "ACPI / battery: Add quirk for Asus GL502VSK and UX305LA" | expand

Commit Message

Kai-Heng Feng Feb. 2, 2019, 3:37 p.m. UTC 
From: Hans de Goede <hdegoede@redhat.com>

BugLink: https://bugs.launchpad.net/bugs/1745032

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.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Daniel Drake <drake@endlessm.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(backported from commit 19fffc8450d4378580a8f019b195c4617083176f)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/acpi/battery.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 6fe6b2e37334..5b4e0a49ddc4 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))