OpenRGB lavender stack: colour script, user units, resume watcher

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

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+# rgb-lavender
+
+Catppuccin Latte lavender (`#7287FD`) on every RGB controller in the cachyos-gaming desktop
+(ASUS Z790 Hero build), driven by OpenRGB and kept that way across suspend/resume.
+
+## Pieces
+
+| File | Role |
+|---|---|
+| `bin/rgb-lavender` | Applies the colour to every device, resolving them by name. Tunables at the top (`RGB_COLOR`, sizes, headers). |
+| `bin/rgb-resume-watch` | Listens on the system bus for logind `PrepareForSleep(false)` and restarts the OpenRGB server, which re-runs `rgb-lavender`. |
+| `systemd/openrgb-server.service` | `openrgb --server --noautoconnect` as a user service. |
+| `systemd/rgb-lavender.service` | Oneshot, `PartOf=openrgb-server.service` → re-applies whenever the server (re)starts. |
+| `systemd/rgb-resume-watch.service` | Runs the watcher. Pure user-level, no root sleep hook. |
+
+## Why the resume watcher
+
+Corsair Commander Core XT, Lighting Node Pro and the Aura headers run in *direct* mode, which only
+lives in controller RAM. After s2ram the USB controllers re-enumerate and lose it: XT fans go dark,
+the rest fall back to firmware defaults, and the ENE DRAM drops off I2C until re-detected. The
+login-time oneshot never re-runs, so the watcher does it for you (~10 s after wake).
+
+## Gotchas (learned the hard way)
+
+- **Always write the whole device.** A zone-only direct write starves the other zones and they go dark.
+- Lighting Node Pro channels default to 14 LEDs — size to 204; `--size` must travel with mode+colour.
+- Aura addressable headers start at 0 LEDs; same rule. Commander Core XT auto-sizes.
+- ENE DRAM is firmware-static and survives boots; Glorious Model O detection is flaky and is skipped if absent.
+- The `recv_select failed receiving magic` spam in the server log is just the detection poll in `rgb-lavender`.
+
+## Install
+
+```sh
+./install.sh
+RGB_COLOR=ca9ee6 rgb-lavender   # try another colour ad hoc
+```

bin/rgb-lavender

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+#!/bin/bash
+# Apply a single colour to every RGB controller in this machine (ASUS Z790 Hero build).
+# See ~/Nextcloud/Notes/Linux_RGB_OpenRGB_Catppuccin.md for the MSI/Fedora sibling and the why.
+#
+# Tunables (env overrides):
+#   RGB_COLOR   hex, no '#'.  Default: Catppuccin Latte lavender.
+#   ASUS_SIZE   LED count for each Aura Addressable header (Aura max 120; oversizing is harmless in direct).
+#   NODEPRO_SIZE LED count per Lighting Node Pro channel (max 204).
+#   ASUS_ZONES  which addressable headers to size (space list). Empty headers are still written by the
+#               device-wide pass, sizing them just lengthens the buffer.
+set -u
+RGB_COLOR=${RGB_COLOR:-7287FD}
+ASUS_SIZE=${ASUS_SIZE:-120}
+ASUS_ZONES=${ASUS_ZONES:-"1 2 3 4"}
+NODEPRO_SIZE=${NODEPRO_SIZE:-204}
+SERVER=${SERVER:-127.0.0.1:6742}
+
+o() { openrgb --client "$SERVER" "$@" 2>&1 | grep -viE '^(client|connected|network)|^$'; }
+
+# Wait until the server has actually finished detection (it accepts connections early).
+# Count DISTINCT device names — the client double-connects, so raw line counts are doubled
+# and a half-detected list passes a numeric threshold. Require the controllers we care about.
+REQUIRED=("ENE DRAM" "Corsair Commander Core XT" "Corsair Lighting Node Pro" "ASUS ROG MAXIMUS Z790 HERO")
+for _ in $(seq 1 90); do
+  l=$(openrgb --client "$SERVER" --list-devices 2>/dev/null | grep -E '^[0-9]+: ')
+  ok=1; for r in "${REQUIRED[@]}"; do echo "$l" | grep -qF "$r" || ok=0; done
+  [ "$ok" = 1 ] && break
+  sleep 1
+done
+sleep 2   # let the last-detected device settle before writing
+
+# Device indices are resolved by name so re-detection order changes don't matter.
+# Client double-connects → every device is listed twice; take the lowest index per name.
+list=$(openrgb --client "$SERVER" --list-devices 2>/dev/null | grep -E '^[0-9]+: ')
+idx() { echo "$list" | grep -F "$1" | head -1 | cut -d: -f1; }
+idxs() { echo "$list" | grep -F "$1" | cut -d: -f1 | sort -n | head -n "$2"; }
+
+# ENE DRAM x2 — firmware static, persists across boots.
+for d in $(idxs 'ENE DRAM' 2); do o --device "$d" --mode static --color "$RGB_COLOR"; done
+
+# Corsair Commander Core XT — ports 1-4 = fans, auto-sized by the controller (34/34/34/16). Direct only.
+# Always write the WHOLE device: a zone-only write starves the other ports and they go dark.
+d=$(idx 'Corsair Commander Core XT'); [ -n "$d" ] && o --device "$d" --mode direct --color "$RGB_COLOR"
+
+# Corsair Lighting Node Pro — ch1 = ARGB strip, ch2 = 3 top fans + rear fan via LED hub.
+# Channels default to 14 LEDs, which lights nothing useful; size both to the 204 max (surplus falls off).
+# --size must travel with mode+colour. Then a device-wide write so neither channel starves in direct.
+d=$(idx 'Corsair Lighting Node Pro')
+if [ -n "$d" ]; then
+  for z in 0 1; do o --device "$d" --zone "$z" --size "$NODEPRO_SIZE" --mode direct --color "$RGB_COLOR"; done
+  o --device "$d" --mode direct --color "$RGB_COLOR"
+fi
+
+# ASUS Aura — addressable headers start at 0 LEDs; size them (must travel with mode+colour),
+# then a device-wide write so the mainboard zone is covered too.
+d=$(idx 'ASUS ROG MAXIMUS Z790 HERO')
+if [ -n "$d" ]; then
+  for z in $ASUS_ZONES; do o --device "$d" --zone "$z" --size "$ASUS_SIZE" --mode direct --color "$RGB_COLOR"; done
+  o --device "$d" --mode direct --color "$RGB_COLOR"
+fi
+
+# Glorious Model O — stored in mouse firmware. Detection is flaky; skip silently if absent.
+d=$(idx 'Glorious Model O'); [ -n "$d" ] && o --device "$d" --mode custom --color "$RGB_COLOR"
+exit 0

bin/rgb-resume-watch

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+#!/bin/bash
+# Re-apply RGB after suspend/resume. Direct-mode Corsair/Aura state is volatile and the USB
+# controllers re-enumerate on wake, so restart the OpenRGB server (rgb-lavender.service is
+# PartOf it and re-runs automatically). Pure user-level: watches logind's PrepareForSleep.
+set -u
+exec dbus-monitor --system "type='signal',interface='org.freedesktop.login1.Manager',member='PrepareForSleep'" |
+while read -r line; do
+  case "$line" in
+    *"boolean false"*)
+      sleep 3   # let USB finish re-enumerating before re-detecting
+      systemctl --user restart openrgb-server.service
+      ;;
+  esac
+done

install.sh

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+#!/bin/bash
+# Install scripts + user units and start the stack.
+set -eu
+cd "$(dirname "$0")"
+install -Dm755 bin/rgb-lavender bin/rgb-resume-watch -t ~/.local/bin
+install -Dm644 systemd/*.service -t ~/.config/systemd/user
+systemctl --user daemon-reload
+systemctl --user enable --now openrgb-server.service rgb-resume-watch.service

systemd/openrgb-server.service

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+[Unit]
+Description=OpenRGB SDK server
+After=graphical-session.target
+
+[Service]
+ExecStart=/usr/bin/openrgb --server --noautoconnect
+Restart=on-failure
+RestartSec=3
+
+[Install]
+WantedBy=default.target

systemd/rgb-lavender.service

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+[Unit]
+Description=Apply Catppuccin lavender to all RGB devices
+Requires=openrgb-server.service
+After=openrgb-server.service
+PartOf=openrgb-server.service
+
+[Service]
+Type=oneshot
+ExecStart=%h/.local/bin/rgb-lavender
+
+[Install]
+WantedBy=openrgb-server.service

systemd/rgb-resume-watch.service

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+[Unit]
+Description=Re-apply RGB colour after resume from suspend
+After=openrgb-server.service
+
+[Service]
+ExecStart=%h/.local/bin/rgb-resume-watch
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=default.target