From ce83a8e655fcd872f8d5c80e5d1f6a53fcd5841e Mon Sep 17 00:00:00 2001 From: Bernardo Magri Date: Wed, 8 Jul 2026 14:52:40 +0100 Subject: [PATCH] docs(backlog): record PPD-vs-TLP default power backend as a Decision MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Bernardo asked whether TLP would be more power-efficient and worth making the default. Logged in § Decisions with the evidence gathered 2026-07-08: TLP's gain is idle-only and unquantified (its own maintainer won't cite numbers), the sibling distro Omarchy tried TLP-for-battery and reverted to PPD, and TLP-default would rework the powerprofilesctl-based profile UX. Agent recommendation: keep PPD, chase battery via targeted low-risk tweaks + keep TLP the one-line opt-in. Decision itself stays with Bernardo. Co-Authored-By: Claude Opus 4.8 --- agent/BACKLOG.md | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/agent/BACKLOG.md b/agent/BACKLOG.md index f752c10..1ee7926 100644 --- a/agent/BACKLOG.md +++ b/agent/BACKLOG.md @@ -327,3 +327,29 @@ decide. Firefox is installed and are skipped otherwise, so the remaining call is only: ship a browser active in the suite, or stay browserless-by-default? + +- **Default power backend — PPD vs TLP:** (raised by Bernardo 2026-07-08: + would TLP be more power-efficient, and should it be the default?) + TLP does get more *idle* battery life, but only from device-level knobs + PPD deliberately omits — PCIe ASPM, disk/NVMe link PM, USB autosuspend, + runtime PM — which are the same knobs behind NVMe/USB flakiness that + pillar 1 (rock-stable, never fight your machine) guards against. + **Evidence (2026-07-08):** no credible hard-watt benchmarks exist — TLP's + own maintainer declines to quote any ("measure on your hardware") and says + PPD's power-saver gives *similar* savings under load; TLP's edge is + idle-only (linrunner.de/tlp/faq/ppd.html — PPD covers a *subset* of TLP, + "no settings to reduce consumption when the CPU is idle"). Our sibling + distro **Omarchy** ran this exact experiment — a "replace Power Profiles + with TLP for battery" guide — and the author **reverted to PPD** ("more + headaches and weird issues"); Omarchy shipped PPD auto-switching instead + (basecamp/omarchy#3907). PPD 3.4.0 now does AC/battery auto-switching, + closing part of TLP's UX gap. **Cost of TLP-default:** TLP has no live + D-Bus profile API, so the `powermgmt` menu + Waybar profile indicator + + low-battery auto power-saver (all `powerprofilesctl`) would need a rework — + it's not a one-line backend swap. **Agent rec (evidence, not a decision): + keep PPD default;** chase battery via targeted low-risk tweaks (PCIe ASPM + policy, battery-side EPP, the charge *start* threshold, PPD auto-switching) + and keep TLP the documented one-line opt-in it already is + (`nomarchy.system.power.backend = "tlp"`). Options: (i) status quo + + targeted tweaks [rec]; (ii) TLP default (reworks the profile UX); + (iii) nothing.