Re: [PATCH] ACPI: battery: Fix bogus cycle count values on systems without _BIX

[Rafael J. Wysocki (Intel)]

On Tue, Sep 1, 2026 at 10:11 PM Armin Wolf <W_Armin@xxxxxx> wrote:
>
> Am 07.08.26 um 01:38 schrieb Armin Wolf:
>
> > Devices supporting only the legacy _BIF ACPI control method cannot
> > know the cycle count of the associated battery, so cycle_count always
> > remains 0. Claiming support for POWER_SUPPLY_PROP_CYCLE_COUNT on
> > such devices can thus mislead userspace applications and prevents
> > power supply extensions from supplying correct cycle count values.
> >
> > Fix this by not claiming support for POWER_SUPPLY_PROP_CYCLE_COUNT
> > on devices without _BIX.
>
> Any thoughts on this? I tested it on my device, and so far everything seems
> to work flawlessly.

It looks good overall, but it is quite substantial, which is why it
didn't make it into 7.3-rc1.

I'm planning to apply it for 7.4.

> > Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
> > ---
> >   drivers/acpi/battery.c | 131 +++++++++++++++++++++++++++++++++++------
> >   1 file changed, 113 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
> > index 0084f308b790..b64f876f93cb 100644
> > --- a/drivers/acpi/battery.c
> > +++ b/drivers/acpi/battery.c
> > @@ -324,7 +324,9 @@ static int acpi_battery_get_property(struct power_supply *psy,
> >       return ret;
> >   }
> >
> > -static const enum power_supply_property charge_battery_props[] = {
> > +/* For devices supporting the _BIX ACPI control method */
> > +
> > +static const enum power_supply_property charge_battery_extended_props[] = {
> >       POWER_SUPPLY_PROP_STATUS,
> >       POWER_SUPPLY_PROP_PRESENT,
> >       POWER_SUPPLY_PROP_TECHNOLOGY,
> > @@ -342,7 +344,7 @@ static const enum power_supply_property charge_battery_props[] = {
> >       POWER_SUPPLY_PROP_SERIAL_NUMBER,
> >   };
> >
> > -static const enum power_supply_property charge_battery_full_cap_broken_props[] = {
> > +static const enum power_supply_property charge_battery_full_cap_broken_extended_props[] = {
> >       POWER_SUPPLY_PROP_STATUS,
> >       POWER_SUPPLY_PROP_PRESENT,
> >       POWER_SUPPLY_PROP_TECHNOLOGY,
> > @@ -356,7 +358,7 @@ static const enum power_supply_property charge_battery_full_cap_broken_props[] =
> >       POWER_SUPPLY_PROP_SERIAL_NUMBER,
> >   };
> >
> > -static const enum power_supply_property energy_battery_props[] = {
> > +static const enum power_supply_property energy_battery_extended_props[] = {
> >       POWER_SUPPLY_PROP_STATUS,
> >       POWER_SUPPLY_PROP_PRESENT,
> >       POWER_SUPPLY_PROP_TECHNOLOGY,
> > @@ -374,7 +376,7 @@ static const enum power_supply_property energy_battery_props[] = {
> >       POWER_SUPPLY_PROP_SERIAL_NUMBER,
> >   };
> >
> > -static const enum power_supply_property energy_battery_full_cap_broken_props[] = {
> > +static const enum power_supply_property energy_battery_full_cap_broken_extended_props[] = {
> >       POWER_SUPPLY_PROP_STATUS,
> >       POWER_SUPPLY_PROP_PRESENT,
> >       POWER_SUPPLY_PROP_TECHNOLOGY,
> > @@ -388,6 +390,68 @@ static const enum power_supply_property energy_battery_full_cap_broken_props[] =
> >       POWER_SUPPLY_PROP_SERIAL_NUMBER,
> >   };
> >
> > +/* For devices supporting only the _BIF ACPI control method */
> > +
> > +static const enum power_supply_property charge_battery_props[] = {
> > +     POWER_SUPPLY_PROP_STATUS,
> > +     POWER_SUPPLY_PROP_PRESENT,
> > +     POWER_SUPPLY_PROP_TECHNOLOGY,
> > +     POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
> > +     POWER_SUPPLY_PROP_VOLTAGE_NOW,
> > +     POWER_SUPPLY_PROP_CURRENT_NOW,
> > +     POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
> > +     POWER_SUPPLY_PROP_CHARGE_FULL,
> > +     POWER_SUPPLY_PROP_CHARGE_NOW,
> > +     POWER_SUPPLY_PROP_CAPACITY,
> > +     POWER_SUPPLY_PROP_CAPACITY_LEVEL,
> > +     POWER_SUPPLY_PROP_MODEL_NAME,
> > +     POWER_SUPPLY_PROP_MANUFACTURER,
> > +     POWER_SUPPLY_PROP_SERIAL_NUMBER,
> > +};
> > +
> > +static const enum power_supply_property charge_battery_full_cap_broken_props[] = {
> > +     POWER_SUPPLY_PROP_STATUS,
> > +     POWER_SUPPLY_PROP_PRESENT,
> > +     POWER_SUPPLY_PROP_TECHNOLOGY,
> > +     POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
> > +     POWER_SUPPLY_PROP_VOLTAGE_NOW,
> > +     POWER_SUPPLY_PROP_CURRENT_NOW,
> > +     POWER_SUPPLY_PROP_CHARGE_NOW,
> > +     POWER_SUPPLY_PROP_MODEL_NAME,
> > +     POWER_SUPPLY_PROP_MANUFACTURER,
> > +     POWER_SUPPLY_PROP_SERIAL_NUMBER,
> > +};
> > +
> > +static const enum power_supply_property energy_battery_props[] = {
> > +     POWER_SUPPLY_PROP_STATUS,
> > +     POWER_SUPPLY_PROP_PRESENT,
> > +     POWER_SUPPLY_PROP_TECHNOLOGY,
> > +     POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
> > +     POWER_SUPPLY_PROP_VOLTAGE_NOW,
> > +     POWER_SUPPLY_PROP_POWER_NOW,
> > +     POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
> > +     POWER_SUPPLY_PROP_ENERGY_FULL,
> > +     POWER_SUPPLY_PROP_ENERGY_NOW,
> > +     POWER_SUPPLY_PROP_CAPACITY,
> > +     POWER_SUPPLY_PROP_CAPACITY_LEVEL,
> > +     POWER_SUPPLY_PROP_MODEL_NAME,
> > +     POWER_SUPPLY_PROP_MANUFACTURER,
> > +     POWER_SUPPLY_PROP_SERIAL_NUMBER,
> > +};
> > +
> > +static const enum power_supply_property energy_battery_full_cap_broken_props[] = {
> > +     POWER_SUPPLY_PROP_STATUS,
> > +     POWER_SUPPLY_PROP_PRESENT,
> > +     POWER_SUPPLY_PROP_TECHNOLOGY,
> > +     POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
> > +     POWER_SUPPLY_PROP_VOLTAGE_NOW,
> > +     POWER_SUPPLY_PROP_POWER_NOW,
> > +     POWER_SUPPLY_PROP_ENERGY_NOW,
> > +     POWER_SUPPLY_PROP_MODEL_NAME,
> > +     POWER_SUPPLY_PROP_MANUFACTURER,
> > +     POWER_SUPPLY_PROP_SERIAL_NUMBER,
> > +};
> > +
> >   /* Battery Management */
> >   struct acpi_offsets {
> >       size_t offset;          /* offset inside struct acpi_sbs_battery */
> > @@ -875,6 +939,7 @@ static void __exit battery_hook_exit(void)
> >
> >   static int sysfs_add_battery(struct acpi_battery *battery)
> >   {
> > +     bool extended_info_available = test_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);
> >       struct power_supply_config psy_cfg = {
> >               .drv_data = battery,
> >               .attr_grp = acpi_battery_groups,
> > @@ -888,25 +953,55 @@ static int sysfs_add_battery(struct acpi_battery *battery)
> >
> >       if (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA) {
> >               if (full_cap_broken) {
> > -                     battery->bat_desc.properties =
> > -                         charge_battery_full_cap_broken_props;
> > -                     battery->bat_desc.num_properties =
> > -                         ARRAY_SIZE(charge_battery_full_cap_broken_props);
> > +                     if (extended_info_available) {
> > +                             battery->bat_desc.properties =
> > +                                     charge_battery_full_cap_broken_extended_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(charge_battery_full_cap_broken_extended_props);
> > +                     } else {
> > +                             battery->bat_desc.properties =
> > +                                     charge_battery_full_cap_broken_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(charge_battery_full_cap_broken_props);
> > +                     }
> >               } else {
> > -                     battery->bat_desc.properties = charge_battery_props;
> > -                     battery->bat_desc.num_properties =
> > -                         ARRAY_SIZE(charge_battery_props);
> > +                     if (extended_info_available) {
> > +                             battery->bat_desc.properties =
> > +                                     charge_battery_extended_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(charge_battery_extended_props);
> > +                     } else {
> > +                             battery->bat_desc.properties =
> > +                                     charge_battery_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(charge_battery_props);
> > +                     }
> >               }
> >       } else {
> >               if (full_cap_broken) {
> > -                     battery->bat_desc.properties =
> > -                         energy_battery_full_cap_broken_props;
> > -                     battery->bat_desc.num_properties =
> > -                         ARRAY_SIZE(energy_battery_full_cap_broken_props);
> > +                     if (extended_info_available) {
> > +                             battery->bat_desc.properties =
> > +                                     energy_battery_full_cap_broken_extended_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(energy_battery_full_cap_broken_extended_props);
> > +                     } else {
> > +                             battery->bat_desc.properties =
> > +                                     energy_battery_full_cap_broken_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(energy_battery_full_cap_broken_props);
> > +                     }
> >               } else {
> > -                     battery->bat_desc.properties = energy_battery_props;
> > -                     battery->bat_desc.num_properties =
> > -                         ARRAY_SIZE(energy_battery_props);
> > +                     if (extended_info_available) {
> > +                             battery->bat_desc.properties =
> > +                                     energy_battery_extended_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(energy_battery_extended_props);
> > +                     } else {
> > +                             battery->bat_desc.properties =
> > +                                     energy_battery_props;
> > +                             battery->bat_desc.num_properties =
> > +                                     ARRAY_SIZE(energy_battery_props);
> > +                     }
> >               }
> >       }
> >