suspend: switch from deep -> s2idle for darp11

[kajusnau]

Description of Changes

1. Darp11: switch to s2idle suspension:
   • switch from deep to s2idle suspension on darp11 target
   • s2idle suspension offers less energy saving, but a lot more compared to simply leaving the system on (ref)
   • s2idle does not power off most hardware, so the GPU does not become wedged
2. Expanded power-manager cfg:
   • changed allowSuspend option to suspend.enable
   • added suspend.mode option to allow changing suspension mode on any target.
     • suspension mode is set via mem_sleep_default kernel parameter
     • it's also possible to do this via sleep.conf.d(5), but in my testing it disabled keyboard wakeup
3. Other:
   • Changed host config to ignore power button short press
   • Re-enabled idleManagement on demo-tower-mk1 and tower-5080

Note

s2idle suspension is distinct from typical deep suspension. Some differences include:

• power LEDs will not pulsate in s2idle suspension
• fans may spin during and after suspension in s2idle mode
• wakeup from s2idle should be faster in most cases compared to regular deep suspension

Type of Change

• New Feature
• Bug Fix
• Improvement / Refactor

Related Issues / Tickets

Addresses (does not fully fix) https://jira.tii.ae/browse/SSRCSP-7016
Fixes https://jira.tii.ae/browse/SSRCSP-7932

Checklist

• Clear summary in PR description
• Detailed and meaningful commit message(s)
• Commits are logically organized and squashed if appropriate
• Contribution guidelines followed
• Ghaf documentation updated with the commit - https://tiiuae.github.io/ghaf/
• Author has run make-checks and it passes
• All automatic GitHub Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing Instructions

Applicable Targets

• Orin AGX aarch64
• Orin NX aarch64
• Lenovo X1 x86_64
• Dell Latitude x86_64
• System 76 x86_64

Installation Method

• Requires full re-installation
• Can be updated with nixos-rebuild ... switch
• Other:

Test Steps To Verify:

1. Verify https://jira.tii.ae/browse/SSRCSP-7016 is addressed
2. (Optional) check battery usage on darp11-b when suspended
   • In my testing, I found approx. 10%/hr battery usage in s2idle mode
3. Verify power button short press no longer initiates system shutdown
4. Verify power button long press still shuts down the system
   • "Long press" time is determined by the firmware. On the darp11, it seem to be around 5 seconds, on x1 gen 11 it may be up to 10.

[milva-unikie]

Tested with system76-darp11-b-storeDisk-debug-installer

Issues

• Screen does not turn on after automatic suspension. The device suspends after 15 minutes and when you press the power button shortly it wakes up and ssh works. The screen however does not turn on. I sent the logs to Kajus.

Working

• s2idle suspension works from the power menu and from the lock screen. The best way to wake up the laptop seems to be a short press on the power button.
• Device is suspended if the lid is closed without charger connected.
• In my test the laptop used 12 % of battery during 80 minute suspension. Not bad.
• Short power button press does not turn the laptop off anymore, long press still does.

[milva-unikie]

Tested on Darter Pro (new image)

All good now!

• Automatic suspension is fixed, the display turns on after suspension
• Other types of suspension work with one exception
  • Laptop is not suspended when the lid is closed. This issue is not related to this PR, same happens on X1 with mainline. I opened a bug for it https://jira.tii.ae/browse/SSRCSP-7968

[kajusnau]

Latest fix includes toggling the display on and back off right before suspension.
This is questionable, but it appears to fix the issue where the GPU might be in a low power state if the display is left off for 5+ minutes. Briefly turning on the display seems to make the GPU wake up, which prevents it from becoming wedged once suspension occurs.

I tried other options, like changing i915 power management settings, force-disabling PCI power management for the GPU, and others, but none seem to address this specific issue.