From 6d0f6f490899ad02b8328a176550a1d003fb6163 Mon Sep 17 00:00:00 2001
From: Matthias Ringwald <matthias@ringwald.ch>
Date: Thu, 6 Jul 2023 12:26:55 +0200
Subject: [PATCH] gatt_client: retry setup eatt connection if there was a setup
 collision

---
 src/ble/gatt_client.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/ble/gatt_client.c b/src/ble/gatt_client.c
index 288575080..e4d84ca6d 100644
--- a/src/ble/gatt_client.c
+++ b/src/ble/gatt_client.c
@@ -87,6 +87,7 @@ static void gatt_client_classic_retry(btstack_timer_source_t * ts);
 
 #ifdef ENABLE_GATT_OVER_EATT
 static bool gatt_client_le_enhanced_handle_can_send_query(gatt_client_t * gatt_client);
+static void gatt_client_le_enhanced_retry(btstack_timer_source_t * ts);
 #endif
 
 void gatt_client_init(void){
@@ -3124,8 +3125,21 @@ static void gatt_client_le_enhanced_handle_connected(gatt_client_t * gatt_client
                 }
             }
         } else {
-            gatt_client->eatt_state = GATT_CLIENT_EATT_IDLE;
-            status = ERROR_CODE_CONNECTION_REJECTED_DUE_TO_LIMITED_RESOURCES;
+            hci_connection_t * hci_connection = hci_connection_for_handle(gatt_client->con_handle);
+            btstack_assert(hci_connection != NULL);
+            if (hci_connection->att_server.incoming_connection_request){
+                hci_connection->att_server.incoming_connection_request = false;
+                log_info("Collision, retry in 100ms");
+                gatt_client->state = P_W2_L2CAP_CONNECT;
+                // set timer for retry
+                btstack_run_loop_set_timer(&gatt_client->gc_timeout, 100);
+                btstack_run_loop_set_timer_handler(&gatt_client->gc_timeout, gatt_client_le_enhanced_retry);
+                btstack_run_loop_add_timer(&gatt_client->gc_timeout);
+                return;
+            } else {
+                gatt_client->eatt_state = GATT_CLIENT_EATT_IDLE;
+                status = ERROR_CODE_CONNECTION_REJECTED_DUE_TO_LIMITED_RESOURCES;
+            }
         }
     } else {
         gatt_client_eatt_finalize(gatt_client);
@@ -3228,6 +3242,14 @@ static void gatt_client_le_enhanced_setup_l2cap_channel(gatt_client_t * gatt_cli
     }
 }
 
+static void gatt_client_le_enhanced_retry(btstack_timer_source_t * ts){
+    gatt_client_t * gatt_client = gatt_client_for_timer(ts);
+    if (gatt_client != NULL){
+        gatt_client->state = P_W4_L2CAP_CONNECTION;
+        gatt_client_le_enhanced_setup_l2cap_channel(gatt_client);
+    }
+}
+
 static void gatt_client_le_enhanced_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) {
     gatt_client_t *gatt_client;
     gatt_client_t *eatt_client;