Bug#656668: 3.2 has different /sys/class/power

[Ben Hutchings <ben@decadent.org.uk>]

On Fri, Jan 20, 2012 at 01:41:03PM -0600, Adam Heath wrote:
> package: linux-image-3.2.0-1-amd64
> version: 3.2.1-1
> severity: major
> 
> linux 3.2 changed what is available in /sys/class/power_supply.
> wmbattery worked fine with 3.1, but the new 3.2 upgrade broke it.
>
> This is a kernel problem, please change this back.  You can add the
> new ADP1, but don't remove the BAT0.  It's a userspace/kernel
> breakage, the kernel shouldn't be doing that.
 
Please be aware that names like 'BAT0' are provided by firmware and
you should not assume that a battery device name will begin with
'BAT'.

That said, this does look like a bug, since the 'ADP1' device doesn't
have any battery attributes.

> From 3.2:
> ==
> root@urk:~# tree /sys/class/power_supply/ADP1/
> /sys/class/power_supply/ADP1/
> ├── device -> ../../../ACPI0003:00

What does /sys/class/power_supply/ADP1/device/driver point to?
 
[...]
> From 3.1:
> ==
> root@urk:~#  tree /sys/class/power_supply/BAT0/
> /sys/class/power_supply/BAT0/
> ├── alarm
> ├── cycle_count
> ├── device -> ../../../PNP0C0A:00
[...]

What does /sys/class/power_supply/BAT0/device/driver point to?
 
Ben.

-- 
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
                                                              - Albert Camus