From 6a927c5d1990a9391242baa00c5ac71490c50c28 Mon Sep 17 00:00:00 2001
From: Brian Harring <ferringb@chromium.org>
Date: Fri, 25 May 2012 02:21:06 -0700
Subject: [PATCH] hooks/pre-auto-gc: look in sysfs to see if a battery is
 known.

Barring any kernel bugs, if this directory exists and there is
a symlink in there (which will point to the battery object),
that means there is a battery known to the kernel.

No symlink should mean no battery as far as the kernel is concerned.

Change-Id: Ib12819a5bbb816f0ae5ca080e5812a2db08441e9
---
 hooks/pre-auto-gc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hooks/pre-auto-gc b/hooks/pre-auto-gc
index 110e3194..360e5e1f 100755
--- a/hooks/pre-auto-gc
+++ b/hooks/pre-auto-gc
@@ -38,6 +38,11 @@ elif test -x /usr/bin/pmset && /usr/bin/pmset -g batt |
 	grep -q "Currently drawing from 'AC Power'"
 then
 	exit 0
+elif test -d /sys/bus/acpi/drivers/battery && test 0 = \
+  "$(find /sys/bus/acpi/drivers/battery/ -type l | wc -l)";
+then
+	# No battery exists.
+	exit 0
 fi
 
 echo "Auto packing deferred; not on AC"