[Trusty SRU] SRU Justification

[AceLan Kao]

Impact: 
Many of our users are suffering from system shutdown immediately after resume
from S3 due to the low battery warning. It's because the acpi battery driver
will remove and add back the battery sysfs when entering S3(refresh its status),
and it will lead to the issue when EC doesn't reply the commands immediately
and then userspace app can't get the battery status while wakeup, so userspace
app will trigger a shutdowm command for battery volume is too low.

Fix: 
This patch prevents the acpi bettery driver from remove the battery sysfs
when entering S3. It's not only speed up the S3, but also fix the issue
described above.

Testcase: Tested on one HP machine.

This patch is in v3.16-rc1.

Lan Tianyu (1):
  ACPI / battery: Accelerate battery resume callback

 drivers/acpi/battery.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

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2.1.0