From aa535e8268ec962aa69a5d613b37075973ac1d5c Mon Sep 17 00:00:00 2001
From: Mike Ajax <14773392+michaelajax@users.noreply.github.com>
Date: Sun, 30 Aug 2026 09:59:00 -0700
Subject: Suppress USB-C attached callback unless cable state changed from
 disconnected->connected or connected->disconnected

---
 src/typec/usbc.c | 7 ++++++-
 src/typec/usbc.h | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/typec/usbc.c b/src/typec/usbc.c
index ab7dd0b92..5b0e4423a 100644
--- a/src/typec/usbc.c
+++ b/src/typec/usbc.c
@@ -31,6 +31,7 @@ static bool _usbc_inited = false;
 
 // if port is initialized
 static bool _port_inited[TUP_TYPEC_RHPORTS_NUM];
+static bool _port_attached[TUP_TYPEC_RHPORTS_NUM];
 
 // Max possible PD size is 262 bytes
 static uint8_t _rx_buf[64] TU_ATTR_ALIGNED(4);
@@ -95,6 +96,7 @@ bool tuc_init(uint8_t rhport, uint32_t port_type) {
   // Initialize stack
   if (!_usbc_inited) {
     tu_memclr(_port_inited, sizeof(_port_inited));
+    tu_memclr(_port_attached, sizeof(_port_attached));
 
     _usbc_q = osal_queue_create(&_usbc_qdef);
     TU_ASSERT(_usbc_q != NULL);
@@ -131,7 +133,10 @@ void tuc_task_ext(uint32_t timeout_ms, bool in_isr) {
     switch (event.event_id) {
       case TCD_EVENT_CC_CHANGED: {
         bool const attached = event.cc_changed.cc_state[0] != 0 || event.cc_changed.cc_state[1] != 0;
-        tuc_attach_changed_cb(event.rhport, attached);
+        if (_port_attached[event.rhport] != attached) {
+          _port_attached[event.rhport] = attached;
+          tuc_attach_changed_cb(event.rhport, attached);
+        }
         break;
       }
 
diff --git a/src/typec/usbc.h b/src/typec/usbc.h
index fc4773b07..dfc96dee9 100644
--- a/src/typec/usbc.h
+++ b/src/typec/usbc.h
@@ -65,6 +65,7 @@ extern void tcd_int_handler(uint8_t rhport);
 
 bool tuc_pd_data_received_cb(uint8_t rhport, pd_header_t const* header, uint8_t const* dobj, uint8_t const* p_end);
 bool tuc_pd_control_received_cb(uint8_t rhport, pd_header_t const* header);
+// Invoked from tuc_task() only when the derived attachment state changes.
 void tuc_attach_changed_cb(uint8_t rhport, bool attached);
 
 //--------------------------------------------------------------------+
-- 
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