Re: [PATCH] ACPI battery: handle batteries tht report percentage remaining capacity correctly

[Zhang Rui <rui.zhang@intel.com>]

On Wed, 2010-10-13 at 08:18 +0800, Zhang, Rui wrote:
> According to the ACPI spec, some kind of primary battery can
> report percentage battery remaining capacity directly to OS.
> 
> In this case, it reports the LastFullChargedCapacity == 100,
> BatteryPresentRate == 0xFFFFFFFF, and BatteryRemaingCapacity a
> percentage value, which actually means RemainingBatteryPercentage.
> 
> Now we found some battery follows this rule even if it's rechargeable.
> https://bugzilla.kernel.org/show_bug.cgi?id=15979
> 
> Handle these batteries correctly in ACPI battery driver
> so that they won't break userspace.
> 
Forgot to add,

Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
> ---
>  drivers/acpi/battery.c |   38 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 37 insertions(+), 1 deletion(-)
> 
> Index: linux-2.6/drivers/acpi/battery.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/battery.c
> +++ linux-2.6/drivers/acpi/battery.c
> @@ -98,6 +98,7 @@ enum {
>  	 * due to bad math.
>  	 */
>  	ACPI_BATTERY_QUIRK_SIGNED16_CURRENT,
> +	ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY,
>  };
>  
>  struct acpi_battery {
> @@ -412,6 +413,8 @@ static int acpi_battery_get_info(struct 
>  		result = extract_package(battery, buffer.pointer,
>  				info_offsets, ARRAY_SIZE(info_offsets));
>  	kfree(buffer.pointer);
> +	if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
> +		battery->full_charge_capacity = battery->design_capacity;
>  	return result;
>  }
>  
> @@ -448,6 +451,10 @@ static int acpi_battery_get_state(struct
>  	    battery->rate_now != -1)
>  		battery->rate_now = abs((s16)battery->rate_now);
>  
> +	if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags)
> +	    && battery->capacity_now >= 0 && battery->capacity_now <= 100)
> +		battery->capacity_now = (battery->capacity_now *
> +				battery->full_charge_capacity) / 100;
>  	return result;
>  }
>  
> @@ -561,6 +568,33 @@ static void acpi_battery_quirks(struct a
>  	}
>  }
>  
> +/*
> + * According to the ACPI spec, some kinds of primary batteries can
> + * report percentage battery remaining capacity directly to OS.
> + * In this case, it reports the Last Full Charged Capacity == 100
> + * and BatteryPresentRate == 0xFFFFFFFF.
> + *
> + * Now we found some battery reports percentage remaining capacity
> + * even if it's rechargeable.
> + * https://bugzilla.kernel.org/show_bug.cgi?id=15979
> + *
> + * Handle this correctly so that they won't break userspace.
> + */
> +static void acpi_battery_quirks2(struct acpi_battery *battery)
> +{
> +	if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
> +		return ;
> +
> +        if (battery->full_charge_capacity == 100 &&
> +            battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN &&
> +            battery->capacity_now >=0 && battery->capacity_now <= 100) {
> +		set_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags);
> +		battery->full_charge_capacity = battery->design_capacity;
> +		battery->capacity_now = (battery->capacity_now *
> +				battery->full_charge_capacity) / 100;
> +	}
> +}
> +
>  static int acpi_battery_update(struct acpi_battery *battery)
>  {
>  	int result, old_present = acpi_battery_present(battery);
> @@ -586,7 +620,9 @@ static int acpi_battery_update(struct ac
>  	if (!battery->bat.dev)
>  		sysfs_add_battery(battery);
>  #endif
> -	return acpi_battery_get_state(battery);
> +	result = acpi_battery_get_state(battery);
> +	acpi_battery_quirks2(battery);
> +	return result;
>  }
>  
>  /* --------------------------------------------------------------------------
> 
>