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authorHans de Goede <hdegoede@redhat.com>2019-12-10 10:57:51 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-12-16 11:16:57 +0100
commit5b74d1d16e2f5753fcbdecd6771b2d8370dda414 (patch)
tree3ffd5e697c8941f0e79ed851435d33f6ae554519 /drivers/acpi
parentcc99f0ad52467028cb1251160f23ad4bb65baf20 (diff)
downloadlinux-5b74d1d16e2f5753fcbdecd6771b2d8370dda414.tar.gz
ACPI / battery: Use design-cap for capacity calculations if full-cap is not available
The ThunderSoft TS178 tablet's _BIX implementation reports design_capacity
but not full_charge_capacity.

Before this commit this would cause us to return -ENODEV for the capacity
attribute, which userspace does not like. Specifically upower does this:

        if (sysfs_file_exists (native_path, "capacity")) {
                percentage = sysfs_get_double (native_path, "capacity");

Where the sysfs_get_double() helper returns 0 when we return -ENODEV,
so the battery always reads 0% if we return -ENODEV.

This commit fixes this by using the design-capacity instead of the
full-charge-capacity when the full-charge-capacity is not available.

Fixes: b41901a2cf06 ("ACPI / battery: Do not export energy_full[_design] on devices without full_charge_capacity")
Cc: 4.19+ <stable@vger.kernel.org> # 4.19+
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/battery.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 0862d38e51fa..85a6c3c3631c 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -217,7 +217,7 @@ static int acpi_battery_get_property(struct power_supply *psy,
 				     enum power_supply_property psp,
 				     union power_supply_propval *val)
 {
-	int ret = 0;
+	int full_capacity = ACPI_BATTERY_VALUE_UNKNOWN, ret = 0;
 	struct acpi_battery *battery = to_acpi_battery(psy);
 
 	if (acpi_battery_present(battery)) {
@@ -286,12 +286,17 @@ static int acpi_battery_get_property(struct power_supply *psy,
 			val->intval = battery->capacity_now * 1000;
 		break;
 	case POWER_SUPPLY_PROP_CAPACITY:
+		if (ACPI_BATTERY_CAPACITY_VALID(battery->full_charge_capacity))
+			full_capacity = battery->full_charge_capacity;
+		else if (ACPI_BATTERY_CAPACITY_VALID(battery->design_capacity))
+			full_capacity = battery->design_capacity;
+
 		if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN ||
-		    !ACPI_BATTERY_CAPACITY_VALID(battery->full_charge_capacity))
+		    full_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
 			ret = -ENODEV;
 		else
 			val->intval = battery->capacity_now * 100/
-					battery->full_charge_capacity;
+					full_capacity;
 		break;
 	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
 		if (battery->state & ACPI_BATTERY_STATE_CRITICAL)