From 7afcc6fc5db1f3fbcaae0fb7a4e6f5878a7b0530 Mon Sep 17 00:00:00 2001
From: Patrick Mulligan <patjmulligan@protonmail.com>
Date: Sun, 29 Mar 2026 22:03:15 -0400
Subject: [PATCH] feat(deploy): add eGalax touchscreen support for Dell 9030
 AIO

The Dell OptiPlex 9030 AIO's built-in eGalax touchscreen is
misidentified by libinput as a touchpad. Fix:

1. Unbind from usbhid at boot via udev, bind to usbtouchscreen
   kernel module which handles it as absolute input
2. Apply calibration matrix via systemd service after X11 starts
   (swap+invert axes, scale to active panel area 238-1853 x 197-1869)

Also updates hardware comments for Dell 9030 (was HP ProDesk).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 deploy/nixos/hardware/batm3.nix | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/deploy/nixos/hardware/batm3.nix b/deploy/nixos/hardware/batm3.nix
index f037e2e..363c3c9 100644
--- a/deploy/nixos/hardware/batm3.nix
+++ b/deploy/nixos/hardware/batm3.nix
@@ -1,6 +1,6 @@
 # BATM3 Hardware Configuration
-# HP ProDesk 600 G3 DM, Intel i5-7500T, Intel HD 630
-# Temporary board replacement for GeneralBytes BATM3 (ARM Android → x86 NixOS)
+# Dell OptiPlex 9030 AIO, Intel i7-4790S, Intel HD 4600
+# Board replacement for GeneralBytes BATM3 (ARM Android → x86 NixOS)
 
 { config, lib, pkgs, ... }:
 
@@ -21,6 +21,7 @@
 
     kernelModules = [
       "kvm-intel"
+      "usbtouchscreen"
     ];
 
     kernelParams = [
@@ -67,8 +68,11 @@
     hybrid-sleep.enable = false;
   };
 
-  # Serial port access for bill validator/dispenser (USB-serial adapters)
-  # Stable symlinks by adapter serial number (prevents ttyUSB reordering on reboot)
+  # eGalax touchscreen (Dell 9030 AIO built-in panel)
+  # The eGalax HID descriptor confuses libinput (treats it as touchpad).
+  # Fix: unbind from usbhid at boot, bind to usbtouchscreen kernel module,
+  # then apply calibration matrix after X11 starts.
+  # Unbind eGalax from usbhid, bind to usbtouchscreen
   services.udev.extraRules = lib.mkAfter ''
     KERNEL=="ttyS[0-9]*", MODE="0666"
     KERNEL=="ttyUSB[0-9]*", MODE="0666"
@@ -76,5 +80,23 @@
     SUBSYSTEM=="tty", ATTRS{serial}=="DDDLb103Y23", SYMLINK+="ttyF56", MODE="0666"
     SUBSYSTEM=="tty", ATTRS{serial}=="A9YW78OC", SYMLINK+="ttyMEI", MODE="0666"
     SUBSYSTEM=="tty", ATTRS{serial}=="A9ZF8ELY", SYMLINK+="ttyNFC", MODE="0666"
+    ACTION=="add", SUBSYSTEM=="usb", ATTRS{idVendor}=="0eef", ATTRS{idProduct}=="0001", RUN+="${pkgs.bash}/bin/bash -c 'echo $kernel:1.0 > /sys/bus/usb/drivers/usbhid/unbind 2>/dev/null; echo 0eef 0001 > /sys/bus/usb/drivers/usbtouchscreen/new_id 2>/dev/null'"
   '';
+
+  # Apply touchscreen calibration after X11 starts
+  # Matrix: swap X/Y axes, invert both, scale to active panel area (238-1853 x 197-1869)
+  systemd.services.egalax-calibrate = {
+    description = "Calibrate eGalax touchscreen";
+    after = [ "display-manager.service" ];
+    requires = [ "display-manager.service" ];
+    wantedBy = [ "graphical.target" ];
+    serviceConfig = {
+      Type = "oneshot";
+      RemainAfterExit = true;
+      User = "lamassu";
+      Environment = "DISPLAY=:0";
+      ExecStartPre = "${pkgs.coreutils}/bin/sleep 3";
+      ExecStart = "${pkgs.xorg.xinput}/bin/xinput set-prop 'eGalax Inc. USB TouchController' 'Coordinate Transformation Matrix' 0 -1.268 1.147 -1.224 0 1.118 0 0 1";
+    };
+  };
 }