On 5/16/2023 3:41 PM, Sebastian Reichel wrote:
Hi,
On Tue, May 16, 2023 at 01:25:40PM -0500, Mario Limonciello wrote:
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@xxxxxxx>
Suggested-by: Lijo Lazar <Lijo.Lazar@xxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
Good find; the current logic should also break with a desktop PC
once a POWER_SUPPLY_SCOPE_DEVICE battery device is attached (e.g.
a HID device), because it increases the counter.
Yup!
I suppose I can just apply this to my fixes branch since there is
no compile time dependency to the second patch?
Yes, that's correct. I don't see a problem with the other patch going
through
another tree.
-- Sebastian
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
