F28 System Wide Change: Improved Laptop Battery Life

[Jan Kurik]

= System Wide Change: Improved Laptop Battery Life =
https://fedoraproject.org/wiki/Changes/ImprovedLaptopBatteryLife

Change owner(s):
* Hans de Goede <hdegoede AT redhat DOT com >

Improve Fedora (Workstation) Battery Life by enabling various hardware
power-saving features by default.


== Detailed Description ==
The initial focus of this change is to enable to following 3 hardware
power-saving features by default:

* A new SATA link-powermanagement-policy has been written which
mirrors Windows defaults: med_power_with_dipm, this has been merged
for kernel 4.15, as part of this change this new policy will be the
default on all Intel mobile chipsets. This saves aprox. 1.0 - 1.5
Watts of power on an idle laptop.
* Enable Intel HDA codec power-saving by default with a 1 second
timeout. This saves aprox. 0.4 Watts of power on an idle laptop.
* Enable USB autosuspend for USB bluetooth receivers by default. If
all other USB devices on the laptop also have USB auto-suspend enabled
(which typically is true) this saves aprox. 0.4 Watts of power on an
idle laptop.

Depending on how much time this takes, this list may be extended.


== Scope ==
* Proposal owners:
Write kernel patches adding new policies / setting the defaults where
necessary and merge these upstream (done for the new SATA
link-pm-policy and for allowing USB autosuspend for btusb),
temporarily add these patches to the Fedora kernels where necessary
and set the Kconfig options to enable these features by default.

* Other developers:
This should not impact other developers, but e.g. developers working
on bluetooth may see regressions which have their root cause in this
change. All the changes will have kernel cmdline options to disable
them, so that developers can easily ask users to test if these changes
are the cause of any problems.

* Release engineering:
https://pagure.io/releng/issue/7171

* Policies and guidelines:
The policies and guidelines do not need to be updated.

* Trademark approval:
Not needed for this Change.
-- 
Jan Kuřík
Platform & Fedora Program Manager
Red Hat Czech s.r.o., Purkynova 99/71, 612 45 Brno, Czech Republic