Commit da943564 authored May 16, 2023 by Mario Limonciello Committed by Greg Kroah-Hartman Jun 21, 2023

power: supply: Fix logic checking if system is running from battery



[ Upstream commit 95339f40a8b652b5b1773def31e63fc53c26378a ]

The logic used for power_supply_is_system_supplied() counts all power
supplies and assumes that the system is running from AC if there is
either a non-battery power-supply reporting to be online or if no
power-supplies exist at all.

The second rule is for desktop systems, that don't have any
battery/charger devices. These systems will incorrectly report to be
powered from battery once a device scope power-supply is registered
(e.g. a HID device), since these power-supplies increase the counter.

Apart from HID devices, recent dGPUs provide UCSI power supplies on a
desktop systems. The dGPU by default doesn't have anything plugged in so
it's 'offline'. This makes power_supply_is_system_supplied() return 0
with a count of 1 meaning all drivers that use this get a wrong judgement.

To fix this case adjust the logic to also examine the scope of the power
supply. If the power supply is deemed a device power supply, then don't
count it.

Cc: Evan Quan <Evan.Quan@amd.com>
Suggested-by: Lijo Lazar <Lijo.Lazar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 7a7d6c86

drivers/power/supply/power_supply_core.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -350,6 +350,10 @@ static int __power_supply_is_system_supplied(struct device dev, void data)
		struct power_supply *psy = dev_get_drvdata(dev);
		unsigned int *count = data;

		if (!psy->desc->get_property(psy, POWER_SUPPLY_PROP_SCOPE, &ret))
		if (ret.intval == POWER_SUPPLY_SCOPE_DEVICE)
		return 0;

		(*count)++;
		if (psy->desc->type != POWER_SUPPLY_TYPE_BATTERY)
		if (!psy->desc->get_property(psy, POWER_SUPPLY_PROP_ONLINE,
		@@ -368,8 +372,8 @@ int power_supply_is_system_supplied(void)
		__power_supply_is_system_supplied);

		/*
		* If no power class device was found at all, most probably we are
		* running on a desktop system, so assume we are on mains power.
		* If no system scope power class device was found at all, most probably we
		* are running on a desktop system, so assume we are on mains power.
		*/
		if (count == 0)
		return 1;