Control: tag -1 moreinfo
On Thu, 2013-02-21 at 00:24 +0100, Stefan Nagy wrote:
> Package: src:linux
> Version: 3.2.35-2
> Severity: normal
>
> Dear Maintainer,
>
> while my BIOS/UEFI reports a battery charge capacity of 92% for my notebook-
> battery, upower still reports a charge capacity of 100% (AFAIK upower gets this
> information from the kernel - I believe this to be a kernel ACPI bug).
The kernel driver doesn't do anything very interesting so it's actually
very likely a BIOS bug.
> I
> suspect this issue to be part of my power problems reported in bug #695634 and
> bug #684186 - my notebook fails to execute action (hibernate) on critical
> battery condition. I'll add the information provided by UEFI (1.) and by upower
> (2.).
>
> (1.) Here's the information provided by the HP UEFI Support Environment:
> Charge Capacity: 92%
[...]
> Design Capacity: 5400 mAh
> Full Charge Capacity: 5020 mAh
[...]
> Design Voltage: 11100 mV
OK, 5020/5400 ~= 0.92.
[...]
> (2.) Here's the information provided by upower ('upower --dump'):
> Device: /org/freedesktop/UPower/devices/battery_BAT1
> native-path:
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:02/PNP0C0A:00/power_supply/BAT1
> vendor: 13-17
> model: Venturi
> serial: 01317 01/24/2012
> power supply: yes
> updated: Wed Feb 20 23:57:03 2013 (23 seconds ago)
> has history: yes
> has statistics: yes
> battery
> present: yes
> rechargeable: yes
> state: discharging
> energy: 28.771 Wh
> energy-empty: 0 Wh
> energy-full: 59.94 Wh
> energy-full-design: 59.94 Wh
[...]
5400 mAh * 11100 mV = 59.94 Wh so energy-full-design looks good but
energy-full is wrong.
Apparently, for some systems and batteries, ACPI reports full capacity
as 100 and current level as a percentage. In this case the ACPI battery
driver cannot know what the true full capacity is. Its workaround is to
assume it is equal to full design capacity. Unfortunately there doesn't
seem to be any way to find out whether this workaround was enabled.
Can you send the contents of /sys/class/power_supply/BAT1/uevent so we
at least know what the kernel is reporting?
Ben.
--
Ben Hutchings
Sturgeon's Law: Ninety percent of everything is crap.
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