[PATCH 1/2] power: supply: Use the scope of power supplies to tell if power is system supplied

Mario Limonciello
2023-05-16T18:49:17Z

The logic used for power_supply_is_system_supplied() counts all power
supplies and:
* If no power supplies found assumes AC
* If non-battery power supplies found uses online to determine AC/DC.
- If any are onlined, assumes AC
- Othewise DC.

This logic makes sense for desktop systems that don't export an ACPI
battery, but it fails once you include a dGPU that provides a UCSI
power supply on a desktop system without any other power supplies.

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>
---
drivers/power/supply/power_supply_core.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index ab986dbace16..d57f420ba8c3 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -348,6 +348,10 @@ 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,
@@ -366,8 +370,8 @@ 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;
--
2.34.1