Increase max MTU

scripts/conv_asha_hci.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+
+import argparse
+import re
+from pathlib import Path
+
+def ms_to_ts(ms: str) -> str:
+    millis = int(ms)
+    seconds, milliseconds = divmod(millis, 1000)
+    minutes, seconds = divmod(seconds, 60)
+    hours, minutes = divmod(minutes, 60)
+    return (f'{hours:02}:{minutes:02}:{seconds:02}.{milliseconds:03}')
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('hci_dump', type=Path)
+    parser.add_argument('output', type=Path)
+
+    args = parser.parse_args()
+
+    with open(args.hci_dump, 'r') as hci:
+        lines = hci.readlines()
+
+    out_lines: list[str] = []
+    for line in lines:
+        m = re.match(r'\[ASHA\s+(ERROR|INFO|AUDIO|SCAN)\s+:\s+(\d+) ms\] (.+)', line)
+        if m:
+            out_lines.append(f'[{ms_to_ts(m.group(2))}] LOG -- ASHA {m.group(1)}: {m.group(3)}\n')
+        else:
+            out_lines.append(line)
+
+    with open(args.output, 'w') as out:
+        out.writelines(out_lines)
+

src/asha_bt.cpp

@@ -143,7 +143,7 @@ extern "C" void bt_main()
     /* L2CAP init required for basic btstack functionality */
     LOG_INFO("L2CAP Init.\n");
     l2cap_init();
-    l2cap_set_max_le_mtu(buff_size_sdu);
+    l2cap_set_max_le_mtu(max_mtu);
 
     /* Init the security manager. This takes care of pairing
        with hearing aids, and also allows reconnecting to already

src/hearing_aid.hpp

@@ -17,6 +17,8 @@ constexpr uint32_t ha_cache_size = 4ul;
 
 constexpr uint32_t ha_cache_mask = ha_cache_size - 1ul;
 
+constexpr uint16_t max_mtu = 512;
+
 class HA
 {
 public:
@@ -148,7 +150,7 @@ class HA
 
     // Creating an L2CAP channel requires a receive buffer
     // This is unused, as we only ever send data
-    std::array<uint8_t, sdu_size_bytes> recv_buff = {};
+    std::array<uint8_t, max_mtu> recv_buff = {};
 
     btstack_packet_handler_t l2cap_packet_handler = nullptr;
     btstack_packet_handler_t gatt_packet_handler = nullptr;