Change sleep-inactive-ac-timeout to 1200 to meet eStar 8 requirement

[Rex Tsai]

Based on Energy Star Computers Specification Version 8.0[1] Table 3: Power Management Requirements (page 10)

The energy star spec requests
- The machine shall enter Sleep/Alternative Low Power Mode after no more than 30 minutes of user inactivity. (suspend)
- The machine shall enter Display Sleep Mode shall be set to activate after no more than 15 minutes of user inactivity.

The default settings in focal are
- The machine will enter Sleep/Alternative Low Power Mode in 20 minutes with battery[2]
- The machine is always on with the AC[2]
- Enter Display Sleep Mode in 5 minutes[3]

OEM device team suggested to change org.gnome.settings-daemon.plugins.power sleep-inactive-ac-timeout to 1200 (20 minutes) as default to meet the Power Management Requirements of Energy Star Computers Specification Version 8.0.

[1] Computers Specification Version 8.0 | | ENERGY STAR - https://www.energystar.gov/products/spec/computers_version_8_0_pd
[2] % gsettings list-recursively org.gnome.settings-daemon.plugins.power|grep sleep-
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-timeout 0
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type 'suspend'
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-type 'suspend'
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-timeout 1200
[3] % gsettings list-recursively org.gnome.desktop.session
org.gnome.desktop.session session-name 'ubuntu'
org.gnome.desktop.session idle-delay uint32 300

[Stéphane Verdy (sverdy)]

Note that these settings are additive: for instance, if Display Sleep Mode timeout is 5 mins and Sleep/Alternative Low Power Mode is set to 20 mins, the machine will actually suspend after 20 + 5 = 25 mins.

[Martin Wimpress  (flexiondotorg)]

Following a discussion with the Desktop team in #ubuntu-desktop on 24 March 2020 at 14:47 GMT, we decide to not ship the default in the distro and kindly request the OEM carry their own gscheme override for OEM that require this compliance.

[Sebastien Bacher (seb128)]

Adding some details, the team opinion is that autosuspend on a/c is not a great user experience and we prefer to default to something which isn't going to frustrate users

[hugh chao (hugh712)]

Ok, I will override the setting in oem base image, thanks

[Graham Inggs (ginggs)]

I have a desktop machine running Ubuntu 20.04 Beta and it suspends when left at the login screen.
As in LP: #1759325 , I'm able to adjust the settings for the logged in user, but not for the system.