[ltp] X220: battery related ACPI messages

[Paul Bolle]

0) I've noticed some odd ACPI messages related to a second battery on a
X220:
    $ dmesg -r | grep -e BAT -e Low-level
    <6>[    0.807773] ACPI: Battery Slot [BAT0] (battery present)
    <6>[ 2774.281550] ACPI: Low-level resume complete
    <6>[ 2774.373852] ACPI: \_SB_.PCI0.LPC_.EC__.BAT1: docking
    <3>[ 2774.374371] ACPI: \_SB_.PCI0.LPC_.EC__.BAT1: Unable to dock!
    <6>[ 4238.167651] ACPI: Low-level resume complete
    [...]

So at the first resume, and only at the first resume, it prints (an
informational message and) an error about - what appears to be - docking
of a second battery. However, this X220 has only one (rather ordinary)
battery.

1) Are there X220s with a second battery? What do those laptops print at
resume? Does docking actually make any sense for batteries?

2) Please note that this X220 is a very recent addition. I've upgraded
to v3.11 right after installing Fedora. I haven't investigated whether
previous kernels print these messages too.


Paul Bolle