add hi-res scroll support

src/hid_parser.c

@@ -141,6 +141,29 @@ void handle_main_input(parser_state_t *parser, item_t *item, hid_interface_t *if
     *parser->p_usage = *(parser->p_usage - parser->usage_count);
 }
 
+/* Detect Resolution Multiplier in Feature items, store logical_max+1 as divider.
+   First occurrence only — subsequent multipliers for horizontal scroll are ignored. */
+static void detect_resolution_multiplier(parser_state_t *parser, hid_interface_t *iface) {
+    if (parser->global_usage != HID_USAGE_DESKTOP_MOUSE)
+        return;
+
+    for (int i = 0; i < parser->usage_count; i++) {
+        if (parser->usages[i] == HID_USAGE_DESKTOP_RESOLUTION_MULTIPLIER) {
+            if (iface->mouse.has_resolution_multiplier)
+                return;
+
+            int32_t logical_max = parser->globals[RI_GLOBAL_LOGICAL_MAX].val;
+
+            if (logical_max < 0 || logical_max > 254)
+                return;
+
+            iface->mouse.has_resolution_multiplier = true;
+            iface->mouse.wheel_divider = (uint8_t)(logical_max + 1);
+            return;
+        }
+    }
+}
+
 void handle_main_item(parser_state_t *parser, item_t *item, hid_interface_t *iface) {
     switch (item->hdr.tag) {
         case RI_MAIN_COLLECTION:
@@ -154,6 +177,10 @@ void handle_main_item(parser_state_t *parser, item_t *item, hid_interface_t *ifa
         case RI_MAIN_INPUT:
             handle_main_input(parser, item, iface);
             break;
+
+        case RI_MAIN_FEATURE:
+            detect_resolution_multiplier(parser, iface);
+            break;
     }
 
     parser->usage_count = 0;

src/include/hid_parser.h

@@ -110,6 +110,10 @@ typedef struct {
 
     bool is_found;
     bool uses_report_id;
+
+    /* High-resolution scroll detection from mouse HID descriptor */
+    bool has_resolution_multiplier;
+    uint8_t wheel_divider;
 } mouse_t;
 
 typedef struct hid_interface_t hid_interface_t;

src/mouse.c

@@ -293,6 +293,13 @@ void extract_report_values(uint8_t *raw_report, int len, device_t *state, mouse_
     extract_value(uses_id, &values->wheel, &mouse->wheel, raw_report, len);
     extract_value(uses_id, &values->pan, &mouse->pan, raw_report, len);
 
+    /* Normalize hi-res scroll to standard notches. Standard mice have
+       wheel_divider == 0 (memset), pass through unchanged. */
+    if (mouse->has_resolution_multiplier && mouse->wheel_divider > 1u) {
+        values->wheel /= (int32_t)mouse->wheel_divider;
+        values->pan   /= (int32_t)mouse->wheel_divider;
+    }
+
     if (!extract_value(uses_id, &values->buttons, &mouse->buttons, raw_report, len)) {
         values->buttons = state->mouse_buttons;
     }