Fix OpenRGB compatibility: hidraw instead of libusb, add preinst for upgrade path

.vscode/tasks.json

@@ -44,6 +44,12 @@
       "type": "shell",
       "command": "make clean && make",
       "problemMatcher": "$gcc"
+    },
+    {
+      "label": "make: deb",
+      "type": "shell",
+      "command": "make deb",
+      "problemMatcher": []
     }
   ]
 }

scripts/make-deb.sh

@@ -36,6 +36,51 @@ Description: Remap G1-G9 keys of the Logitech G910
  of a Logitech G910 keyboard to keys or commands.
 EOF
 
+# preinst: stop any running daemon and re-attach the kernel driver BEFORE
+# upgrading.  The old (libusb-based) daemon detached the kernel driver from
+# interface 1; if it was not stopped gracefully, the driver stays detached
+# and the new (hidraw-based) daemon cannot find the device.
+cat > "$STAGING/DEBIAN/preinst" <<'EOF'
+#!/bin/sh
+set -e
+case "$1" in
+    install|upgrade)
+        # Stop any running daemon (old or new).
+        for pid in $(pgrep -f gkeymapper-daemon 2>/dev/null); do
+            kill "$pid" 2>/dev/null || true
+        done
+        sleep 1
+
+        # Re-attach the kernel driver to interface 1 if it was detached by
+        # an older (libusb-based) daemon.
+        for _dev in /sys/bus/usb/devices/*; do
+            _vendor=$(cat "$_dev/idVendor" 2>/dev/null) || continue
+            _product=$(cat "$_dev/idProduct" 2>/dev/null) || continue
+            case "$_vendor" in
+                046d)
+                    case "$_product" in
+                        c32b|c335)
+                            for _iface in "$_dev"/*:*; do
+                                case "$_iface" in
+                                    *:1.*)
+                                        _name=$(basename "$_iface")
+                                        if [ -w /sys/bus/usb/drivers/usbhid/bind ]; then
+                                            echo "$_name" > /sys/bus/usb/drivers/usbhid/bind 2>/dev/null || true
+                                        fi
+                                        ;;
+                                esac
+                            done
+                            ;;
+                    esac
+                    ;;
+            esac
+        done
+        ;;
+esac
+exit 0
+EOF
+chmod 755 "$STAGING/DEBIAN/preinst"
+
 # postinst: reload udev/systemd and enable the user daemon.
 cat > "$STAGING/DEBIAN/postinst" <<'EOF'
 #!/bin/sh
@@ -48,6 +93,10 @@ case "$1" in
             udevadm trigger --subsystem-match=input 2>/dev/null || true
         fi
 
+        # Remove stale service file from old "make install" (PREFIX=/usr/local)
+        # so the new one from /usr takes precedence.
+        rm -f /usr/local/lib/systemd/user/gkeymapper-daemon.service
+
         # Re-attach the kernel driver to interface 1 if it was detached by an
         # older (libusb-based) daemon.  Without this the new (hidraw-based)
         # daemon cannot find /dev/hidraw for interface 1.