Add ROG Flow Z13 trackpad DWT/palm rejection fix

Udev rule to override ID_INPUT_TOUCHPAD_INTEGRATION from external to
internal for the Z13 folio touchpad, plus reference docs and install
script.

CLAUDE.md

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+# ROG Flow Z13 Trackpad Fix
+
+## Overview
+Fixes "Disable while typing" (DWT) + palm rejection on the ASUS ROG Flow Z13
+folio keyboard touchpad. The detachable keyboard connects via USB, which causes
+the touchpad to be misclassified as "external," blocking DWT in KDE Plasma.
+
+## Files
+- `fix-rog-z13-trackpad.sh` — install script (run with sudo)
+- `ROG_Flow_Z13_trackpad_fix_reference.txt` — full documentation
+- `rules/99-rog-z13-touchpad.rules` — standalone copy of the udev rule
+
+## System Files Created
+- `/etc/udev/rules.d/99-rog-z13-touchpad.rules` — marks touchpad as internal
+- `/etc/libinput/local-overrides.quirks` — marks keyboard as internal (optional)
+
+## Root Cause
+Systemd's `65-integration.rules` sets `ID_INPUT_TOUCHPAD_INTEGRATION=external`
+because the USB device is flagged `removable`. Libinput refuses DWT for external
+touchpads. The built-in libinput quirk (`50-system-asus.quirks`) only marks the
+keyboard as internal, not the touchpad — libinput has no `AttrTouchpadIntegration`
+quirk attribute.
+
+## Fix
+A udev rule at priority 99 overrides the property to `internal` after
+`65-integration.rules` (priority 65) sets it to `external`.
+
+## Key Details
+- USB VID:PID = `0b05:1a30`
+- Touchpad event device: `event8` (identified by `ID_INPUT_TOUCHPAD=1`)
+- Touchpad input name: `ASUSTeK Computer Inc. GZ302EA-Keyboard Touchpad`
+- The keyboard and touchpad share the same `LIBINPUT_DEVICE_GROUP`, enabling DWT pairing

ROG_Flow_Z13_trackpad_fix_reference.txt

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+ROG Flow Z13 — Touchpad Palm Rejection / DWT Fix
+==================================================
+Created: 2026-05-13
+Device: ASUS ROG Flow Z13 (folio keyboard, USB 0b05:1a30)
+OS:     CachyOS (Arch Linux)
+KDE:    Plasma 6 (Wayland)
+Issue:  "Disable while typing" checkbox greyed out in Touchpad settings
+
+=====================================================================
+ PROBLEM SUMMARY
+=====================================================================
+
+The ROG Flow Z13's magnetic folio keyboard connects via USB. Since it's
+a detachable keyboard, the kernel marks the USB device as "removable."
+Systemd's 65-integration.rules uses this to set:
+
+  ID_INPUT_TOUCHPAD_INTEGRATION=external
+
+on the touchpad. Libinput refuses to enable "Disable While Typing" (DWT)
+for external touchpads, and KDE respects this by greying out the checkbox.
+
+The libinput quirks system ships a quirk (50-system-asus.quirks) that
+marks the KEYBOARD interface as internal, but there is no libinput quirk
+attribute to mark a TOUCHPAD as internal — so the touchpad remained
+external despite the keyboard being correctly handled.
+
+The USB device exposes these input nodes:
+
+  event3  — Vendor keys          (HID interface 1.0)
+  event4  — Keyboard             (HID interface 1.2)  ← quirk marks internal
+  event7  — Mouse                (HID interface 1.3)
+  event8  — Touchpad             (HID interface 1.3)  ← was marked external
+
+Both keyboard and touchpad share the same LIBINPUT_DEVICE_GROUP, so
+they *can* be paired for DWT — but only if both are internal.
+
+=====================================================================
+ FILES INVOLVED
+=====================================================================
+
+1. /usr/share/libinput/50-system-asus.quirks  [SYSTEM — do not edit]
+   ----------------------------------------------------------------
+   The libinput package ships this file. It includes a quirk:
+
+     [Asus ROG FLow Z13 2025 keyboard]
+     MatchUdevType=keyboard
+     MatchBus=usb
+     MatchVendor=0x0B05
+     MatchProduct=0x1A30
+     AttrKeyboardIntegration=internal
+
+   This correctly marks the keyboard interface as internal, but since
+   MatchUdevType=keyboard, it does not affect the touchpad.
+
+   This file is overwritten on libinput updates. Do not modify it.
+
+2. /etc/libinput/local-overrides.quirks  [USER — was already present]
+   ----------------------------------------------------------------
+   A broader local override that matches all ASUS USB keyboards:
+
+     [ASUS ROG Flow Z13 All USB Keyboards]
+     MatchUdevType=keyboard
+     MatchBus=usb
+     MatchVendor=0x0B05
+     AttrKeyboardIntegration=internal
+
+   This is redundant with the system quirk above (it's less specific
+   since it matches any ASUS keyboard product ID). It's harmless and
+   can be kept or removed — the system quirk alone is sufficient for
+   the keyboard side. If kept, it serves as a catch-all for future
+   ASUS folio keyboards with different product IDs.
+
+3. /etc/udev/rules.d/99-rog-z13-touchpad.rules  [USER — NEW, created for fix]
+   ----------------------------------------------------------------
+   The actual fix. This udev rule overrides the touchpad's integration
+   type from "external" to "internal":
+
+     ACTION=="add|change", SUBSYSTEM=="input", \
+       ENV{ID_VENDOR_ID}=="0b05", ENV{ID_MODEL_ID}=="1a30", \
+       ENV{ID_INPUT_TOUCHPAD}=="1", \
+       ENV{ID_INPUT_TOUCHPAD_INTEGRATION}="internal"
+
+   How it works:
+   - Matches input events from the Z13 folio (USB 0b05:1a30)
+   - Only affects touchpad devices (ID_INPUT_TOUCHPAD=1)
+   - Runs after systemd's 65-integration.rules (which set it to "external")
+   - Changes ID_INPUT_TOUCHPAD_INTEGRATION to "internal"
+
+   Libinput picks up this udev property at runtime, which:
+   a) Unlocks the "Disable while typing" checkbox in KDE
+   b) Enables DWT behavior (touchpad ignored ~300-500ms after keypress)
+   c) Enables libinput's more aggressive palm rejection defaults for
+      internal touchpads (larger exclusion zones, lower palm thresholds)
+
+=====================================================================
+ REVERTING
+=====================================================================
+
+To undo the fix, delete the udev rule and reload:
+
+    sudo rm /etc/udev/rules.d/99-rog-z13-touchpad.rules
+    sudo udevadm control --reload-rules && sudo udevadm trigger
+
+The keyboard quirks files can remain as-is — they only affect the
+keyboard and don't cause issues on their own.
+
+Optionally also remove:
+
+    sudo rm /etc/libinput/local-overrides.quirks
+
+=====================================================================
+ TROUBLESHOOTING
+=====================================================================
+
+If DWT still doesn't work after applying:
+
+1. Verify the udev rule is loaded:
+     udevadm info --query=property /dev/input/event8 | grep INTEGRATION
+   Should show: ID_INPUT_TOUCHPAD_INTEGRATION=internal
+
+2. Verify the keyboard quirk is applied:
+     sudo libinput quirks list /dev/input/event4
+   Should show: AttrKeyboardIntegration=internal
+
+3. Verify both devices are recognized:
+     sudo libinput list-devices | grep -A15 "Touchpad"
+   Should show: Disable-w-typing: enabled
+
+4. If you changed the event number (e.g. after a kernel update), re-check:
+     sudo libinput list-devices
+   Look for your touchpad and keyboard event numbers, then re-verify.
+
+=====================================================================
+ REFERENCES
+=====================================================================
+
+- libinput Device Quirks:   https://wayland.freedesktop.org/libinput/doc/latest/device-quirks.html
+- Linux Touchpad Dev Guide: https://linuxtouchpad.org/libinput/2022/05/07/disable-while-typing.html
+- libinput DWT docs:         https://wayland.freedesktop.org/libinput/doc/latest/configuration.html#disable-while-typing

fix-rog-z13-trackpad.sh

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+#!/bin/bash
+#
+# fix-rog-z13-trackpad.sh
+# Enables "Disable while typing" (DWT) + palm rejection on the
+# ASUS ROG Flow Z13 folio keyboard touchpad.
+#
+# Usage:  ./fix-rog-z13-trackpad.sh
+#         (must be run as root)
+#
+# Tested on: CachyOS / Arch Linux, KDE Plasma 6, Wayland
+# Applies to: ROG Flow Z13 (2023 & 2025 models, USB 0b05:1a30)
+
+set -euo pipefail
+
+if [ "$(id -u)" -ne 0 ]; then
+  echo "ERROR: This script must be run as root."
+  echo "Usage: sudo ./fix-rog-z13-trackpad.sh"
+  exit 1
+fi
+
+echo "=== ROG Flow Z13 Trackpad Fix ==="
+echo ""
+
+# ──────────────────────────────────────
+# 1. udev rule — mark touchpad as internal
+# ──────────────────────────────────────
+UDEV_RULE="/etc/udev/rules.d/99-rog-z13-touchpad.rules"
+
+if [ -f "$UDEV_RULE" ]; then
+  echo "[SKIP] $UDEV_RULE already exists"
+else
+  echo "[CREATE] $UDEV_RULE"
+  cat > "$UDEV_RULE" << 'EOF'
+# ROG Flow Z13 folio keyboard touchpad integration override
+#
+# The Z13's detachable folio keyboard connects via USB (0b05:1a30).
+# The touchpad on this device is correctly exposed as a touchpad, but
+# udev marks it as ID_INPUT_TOUCHPAD_INTEGRATION=external because the
+# USB device is flagged as "removable" (it's a detachable keyboard).
+#
+# Libinput refuses to enable "Disable While Typing" (DWT) for touchpads
+# marked as external, which greyed out the checkbox in KDE Plasma.
+#
+# This rule overrides the integration type to "internal" for the Z13
+# touchpad only, which allows DWT pairing with the keyboard (already
+# marked internal via the libinput quirk in 50-system-asus.quirks).
+
+ACTION=="add|change", SUBSYSTEM=="input", \
+  ENV{ID_VENDOR_ID}=="0b05", ENV{ID_MODEL_ID}=="1a30", \
+  ENV{ID_INPUT_TOUCHPAD}=="1", \
+  ENV{ID_INPUT_TOUCHPAD_INTEGRATION}="internal"
+EOF
+fi
+
+# ──────────────────────────────────────
+# 2. libinput quirk — mark keyboard as internal (belt-and-suspenders)
+# ──────────────────────────────────────
+LIBINPUT_QUIRKS="/etc/libinput/local-overrides.quirks"
+
+# Only create if it doesn't exist; if it does, it may have user customizations
+if [ -f "$LIBINPUT_QUIRKS" ]; then
+  echo "[SKIP] $LIBINPUT_QUIRKS already exists (not overwriting)"
+else
+  echo "[CREATE] $LIBINPUT_QUIRKS"
+  mkdir -p /etc/libinput
+  cat > "$LIBINPUT_QUIRKS" << 'EOF'
+[ROG Flow Z13 All USB Keyboards]
+MatchUdevType=keyboard
+MatchBus=usb
+MatchVendor=0x0B05
+AttrKeyboardIntegration=internal
+EOF
+fi
+
+# ──────────────────────────────────────
+# 3. Apply udev changes
+# ──────────────────────────────────────
+echo ""
+echo "[APPLY] Reloading udev rules..."
+udevadm control --reload-rules
+
+echo "[APPLY] Triggering udev for existing devices..."
+udevadm trigger --subsystem-match=input
+
+echo ""
+echo "=== DONE ==="
+echo ""
+echo "The fix has been applied. To activate it:"
+echo ""
+echo "  1. Log out and log back in (or reboot)"
+echo "  2. Open System Settings -> Touchpad"
+echo "  3. Check \"Disable touchpad when typing\""
+echo ""
+echo "The checkbox should now be available. If the touchpad already"
+echo "feels better at rejecting palm brushes while typing — that's"
+echo "expected. DWT and improved palm rejection both activate when"
+echo "the touchpad is recognized as internal."
+echo ""
+echo "To undo this fix later, run:"
+echo "  sudo rm /etc/udev/rules.d/99-rog-z13-touchpad.rules"
+echo "  sudo rm /etc/libinput/local-overrides.quirks"
+echo "  sudo udevadm control --reload-rules"
+echo "  sudo udevadm trigger --subsystem-match=input"
+echo ""