From f4e7e6a64c6e98c5457317f61679f5b8ca3bc472 Mon Sep 17 00:00:00 2001
From: Ashley Strahle <ash@jackofclubs.com.au>
Date: Tue, 23 Jun 2026 23:44:30 +0000
Subject: [PATCH] Delete Adafruit's DCD, add stubs for missing DCD functions,
 use ESP32 core DCD

---
 extra_script.py | 22 ++++++++++++++++++++++
 src/dcd_stubs.c | 31 +++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 src/dcd_stubs.c

diff --git a/extra_script.py b/extra_script.py
index fda0754..acb79be 100644
--- a/extra_script.py
+++ b/extra_script.py
@@ -1,3 +1,25 @@
 Import("env")
+import os
 
+# Keep allow-multiple-definition for core TinyUSB symbol overlaps
 env.Append(LINKFLAGS=["-Wl,--allow-multiple-definition"])
+
+# Delete the Adafruit library's generic DCD so the ESP32 core's
+# patched version from libarduino_tinyusb.a is used instead.
+# We provide stubs (src/dcd_stubs.c) for the few ISO/SOF functions
+# the ESP32 core's older DCD doesn't implement.
+lib_path = os.path.join(
+    env.subst("$PROJECT_DIR"),
+    ".pio", "libdeps", env.subst("$PIOENV"),
+    "Adafruit TinyUSB Library", "src"
+)
+
+dcd_path = os.path.join(lib_path, "portable", "synopsys", "dwc2", "dcd_dwc2.c")
+backup = dcd_path + ".bak"
+
+if os.path.exists(dcd_path):
+    # Rename .c -> .bak so the build system doesn't compile it
+    os.rename(dcd_path, backup)
+    print("[extra_script] Renamed dcd_dwc2.c -> dcd_dwc2.c.bak (using ESP32 core DCD + project stubs)")
+else:
+    print("[extra_script] dcd_dwc2.c not found at:", dcd_path)
diff --git a/src/dcd_stubs.c b/src/dcd_stubs.c
new file mode 100644
index 0000000..17ab09e
--- /dev/null
+++ b/src/dcd_stubs.c
@@ -0,0 +1,31 @@
+/*
+ * Stub DCD functions required by Adafruit TinyUSB Library's usbd.c
+ * but not provided by ESP32 Arduino core's older libarduino_tinyusb.a.
+ * These are for ISO transfers / SOF interrupt only -- MIDI doesn't use them.
+ */
+#include "tusb.h"
+
+//--------------------------------------------------------------------+
+// SOF (Start of Frame)
+//--------------------------------------------------------------------+
+void dcd_sof_enable(uint8_t rhport, bool enabled) {
+  (void)rhport;
+  (void)enabled;
+}
+
+//--------------------------------------------------------------------+
+// ISO (Isochronous)
+//--------------------------------------------------------------------+
+bool dcd_edpt_iso_alloc(uint8_t rhport, uint8_t dir, uint8_t ep_addr, uint16_t packet_size) {
+  (void)rhport;
+  (void)dir;
+  (void)ep_addr;
+  (void)packet_size;
+  return true;
+}
+
+bool dcd_edpt_iso_activate(uint8_t rhport, tusb_desc_endpoint_t const *p_endpoint_desc) {
+  (void)rhport;
+  (void)p_endpoint_desc;
+  return true;
+}