Research 027/03: the laptop's power management; 026/04: fonts

01-RESEARCH/026-the-graphical-session-as-modules/00-overview.md

@@ -60,5 +60,5 @@ desktops. Measured in [01](01-what-the-workstations-run.md):
 
 - [01 — What the workstations run](01-what-the-workstations-run.md): evidence.
 - [02 — The questions and the options](02-the-questions-and-the-options.md)
-- [04 — Screensaver, displays and menus](04-screensaver-displays-and-menus.md): the lock and idle module, monitor layouts by the monitors' identity, rofi and dmenu behind one launcher seat, the clipboard
+- [04 — Screensaver, displays and menus](04-screensaver-displays-and-menus.md): the lock and idle module, monitor layouts by the monitors' identity, rofi and dmenu behind one launcher seat, the clipboard, fonts
 - [03 — What the predecessor taught](03-what-the-predecessor-taught.md): its 128 modules and 3,395 commits, as patterns to keep and failures not to repeat; shared with research 027.

01-RESEARCH/026-the-graphical-session-as-modules/04-screensaver-displays-and-menus.md

@@ -92,3 +92,26 @@ Three areas the operator named on 2026-10-04, as their own modules. Each sharpen
   - or `clipmenu` (official), which feeds the same dmenu-compatible command as the launcher seat above,
     and needs no archive.
 - **On Wayland** the same seat is held by `cliphist` with `wl-clipboard`, both official.
+
+## Fonts
+
+**Measured:**
+
+- The fonts the desktop uses are **hand-copied files** in the account's font directory, not packages:
+  - a Nerd font for the window manager, the bar and the terminal;
+  - a second one for the prompt;
+  - on one workstation, the same four files twice, once under URL-encoded names;
+  - on the other, a different build of the same font and three more copied from a theme's repository.
+- The system's default monospace is a different font (`Noto Sans Mono`), so anything that asks for
+  `monospace` gets another face than the terminal.
+- The DPI is fixed in an X resource.
+- **Every Nerd font in use is in the official repositories** (Hack, Meslo, Iosevka, JetBrains Mono).
+
+**Starting position:**
+
+- **A `fonts` module:** the official packages, and a fontconfig file it owns that maps `monospace` (and
+  the emoji and symbol fallbacks) to the chosen faces, so every program agrees.
+- The terminal, bar, launcher and prompt modules name the family, not a file.
+- The DPI becomes the display server's setting (issue 168).
+- The copied files are removed by the operator once the packages are in (ADR 0182).
+- Fonts are not a seat: several coexist. The module owns the one place where *the* default is said.

01-RESEARCH/027-the-system-layer-as-modules/00-overview.md

@@ -51,5 +51,5 @@ matters on their own.
 
 - [01 — What the machines run](01-what-the-machines-run.md): evidence.
 - [02 — Candidates and questions](02-candidates-and-questions.md)
-- [03 — The account's own tools](03-the-accounts-own-tools.md): `~/.ssh` as one module's, scripts on every machine, the keyring, mail as events
+- [03 — The account's own tools](03-the-accounts-own-tools.md): `~/.ssh` as one module's, scripts on every machine, the keyring, the laptop's power management, mail as events
 - The predecessor's lessons, shared with research 026: [026/03](../026-the-graphical-session-as-modules/03-what-the-predecessor-taught.md)

01-RESEARCH/027-the-system-layer-as-modules/03-the-accounts-own-tools.md

@@ -126,3 +126,44 @@ The second unlock prompt and the second daemon start go away.
 - **Where it runs:** one long-running module, not per machine (ADR 0198).
 
 The obvious first step is the mail server the mesh already runs.
+
+## Power management on the laptop
+
+*"Power management for the laptop."*
+
+**Measured on the laptop** (a gaming model with a hybrid GPU):
+
+- **The platform profile is driven by a vendor daemon** (`asusd`) and its CLI. The vendor CLI is
+  now in the official repositories; the copy installed came from elsewhere. A predecessor script
+  runs as a user unit and switches the profile every five seconds: quiet on battery, balanced on
+  mains, performance above 50 % CPU.
+- **The hybrid GPU's mode** (now hybrid) is held by a second vendor daemon (`supergfxd`), which is
+  **not** in the official repositories. Kernel-module options for the discrete GPU's power state
+  and its suspend, hibernate and resume units are set by hand. Its own power daemon is masked.
+- **The battery charge limit is 80 %,** set by the vendor daemon.
+- **The lid and power key suspend.** The brightness key is ignored by logind and handled by the
+  vendor-key path. Both are logind drop-ins.
+- **Memory pressure:** compressed swap in RAM (`zram`) beside a swap file and a partition;
+  `systemd-oomd` with drop-ins; a predecessor *memory guard* user unit that notifies before the OOM
+  killer acts.
+- `upower` runs. There is no `power-profiles-daemon`, `tlp`, `auto-cpufreq` or `thermald`, so nothing
+  competes with the vendor daemon, by design.
+
+All of it came from two predecessor modules, one of which was a laptop-model *flavor*. A desktop
+received part of it (research 026/01).
+
+**Starting position:**
+
+- **A hardware module per machine model** (here, the laptop's model). It holds the vendor daemon and
+  its profile configuration, the GPU mode daemon (ADR 0205's case, or the build machine's package
+  repository of research 027 question 1), the discrete GPU's module options and suspend units, the
+  logind drop-ins, the battery charge limit, and the vendor keys and brightness. It is assigned to
+  the one machine of that model, and to any second one later.
+- **The profile switching** moves from a polling script to the module's own long-running code
+  (ADR 0198). It reacts to the power-supply change event instead of polling, and its thresholds
+  become settings (issue 168).
+- **Memory pressure is not the laptop's alone.** `zram` and `systemd-oomd` with the notifier are a
+  `memory-pressure` module, assigned wherever wanted. The swap layout stays the machine's (`kernel`
+  module, question 3).
+- A **`node-power-profile`** seat (vendor daemon, or `power-profiles-daemon` on other hardware)
+  gives the mesh one verb, `profile`, the same on every machine that has one.