pbio/drv/bluetooth_stm32_cc2640: Only restart observe when needed.

CHANGELOG.md

@@ -12,7 +12,12 @@
 - Extensive overhaul of UART and port drivers on all hubs. This affects all
   official LEGO sensors on all hubs.
 
+### Fixed
+- Reduced hanging when broadcasting and observing at the same time with Technic
+  Hub ([support#2206]).
+
 [support#220]: https://github.com/pybricks/support/issues/220
+[support#2206]: https://github.com/pybricks/support/issues/2206
 [pybricks-micropython#208]: https://github.com/pybricks/pybricks-micropython/pull/208
 
 ## [3.6.1] - 2025-03-11

lib/pbio/drv/bluetooth/bluetooth_stm32_cc2640.c

@@ -160,8 +160,8 @@ static const pbdrv_bluetooth_stm32_cc2640_platform_data_t *pdata = &pbdrv_blueto
 #define SCAN_RESTART_INTERVAL 3000
 #define OBSERVE_RESTART_INTERVAL 10000
 static struct etimer scan_restart_timer;
-static struct etimer observe_restart_timer;
-static bool observe_restart_enabled;
+static bool observe_restart_requested;
+static uint32_t observe_restart_time;
 
 /**
  * Converts a ble error code to the most appropriate pbio error code.
@@ -500,7 +500,6 @@ static PT_THREAD(peripheral_scan_and_connect_task(struct pt *pt, pbio_task_t *ta
 
     // temporarily stop observing so we can active scan
     if (is_observing) {
-        observe_restart_enabled = false;
 
         PT_WAIT_WHILE(pt, write_xfer_size);
         GAP_DeviceDiscoveryCancel();
@@ -747,10 +746,8 @@ static PT_THREAD(peripheral_scan_and_connect_task(struct pt *pt, pbio_task_t *ta
 
         device_discovery_done = false;
 
-        PROCESS_CONTEXT_BEGIN(&pbdrv_bluetooth_spi_process);
-        etimer_set(&observe_restart_timer, OBSERVE_RESTART_INTERVAL);
-        PROCESS_CONTEXT_END(&pbdrv_bluetooth_spi_process);
-        observe_restart_enabled = true;
+        observe_restart_time = pbdrv_clock_get_ms();
+        observe_restart_requested = false;
     }
 
     PT_END(pt);
@@ -1073,13 +1070,26 @@ void pbdrv_bluetooth_peripheral_disconnect(pbio_task_t *task) {
 static PT_THREAD(broadcast_task(struct pt *pt, pbio_task_t *task)) {
     pbdrv_bluetooth_value_t *value = task->context;
 
+    static struct {
+        pbdrv_bluetooth_value_t v;
+        uint8_t d[31];
+    } previous_value;
+
     PT_BEGIN(pt);
 
     if (value->size > B_MAX_ADV_LEN) {
         task->status = PBIO_ERROR_INVALID_ARG;
         PT_EXIT(pt);
     }
 
+    // Avoid I/O operations if the user tries to broadcast the same data
+    // over and over in a tight loop.
+    if (is_broadcasting && !memcmp((void *)&previous_value, (void *)value, sizeof(pbdrv_bluetooth_value_t) + value->size)) {
+        task->status = PBIO_SUCCESS;
+        PT_EXIT(pt);
+    }
+    memcpy((void *)&previous_value, (void *)value, sizeof(pbdrv_bluetooth_value_t) + value->size);
+
     // HACK: calling GAP_updateAdvertisingData() repeatedly will cause the
     // Bluetooth chips on Technic and City hubs to eventually lock up. So we
     // call the standard Bluetooth command instead. We still get the vendor-
@@ -1162,10 +1172,8 @@ static PT_THREAD(observe_task(struct pt *pt, pbio_task_t *task)) {
         device_discovery_done = false;
         is_observing = true;
 
-        PROCESS_CONTEXT_BEGIN(&pbdrv_bluetooth_spi_process);
-        etimer_set(&observe_restart_timer, OBSERVE_RESTART_INTERVAL);
-        PROCESS_CONTEXT_END(&pbdrv_bluetooth_spi_process);
-        observe_restart_enabled = true;
+        observe_restart_time = pbdrv_clock_get_ms();
+        observe_restart_requested = false;
     }
 
     task->status = PBIO_SUCCESS;
@@ -1201,11 +1209,16 @@ static PT_THREAD(stop_observe_task(struct pt *pt, pbio_task_t *task)) {
 void pbdrv_bluetooth_stop_observing(pbio_task_t *task) {
     observe_callback = NULL;
     // avoid restarting observing even if this task get queued
-    observe_restart_enabled = false;
+    observe_restart_requested = false;
 
     start_task(task, stop_observe_task, NULL);
 }
 
+void pbdrv_bluetooth_restart_observing_request(void) {
+    observe_restart_requested = true;
+    process_poll(&pbdrv_bluetooth_spi_process);
+}
+
 // Driver interrupt callbacks
 
 void pbdrv_bluetooth_stm32_cc2640_srdy_irq(bool srdy) {
@@ -2250,7 +2263,7 @@ PROCESS_THREAD(pbdrv_bluetooth_spi_process, ev, data) {
         spi_set_mrdy(false);
         bluetooth_reset(RESET_STATE_OUT_LOW);
         bluetooth_ready = pybricks_notify_en = uart_tx_notify_en =
-            is_broadcasting = is_observing = observe_restart_enabled = false;
+            is_broadcasting = is_observing = observe_restart_requested = false;
         conn_handle = peripheral_singleton.con_handle = NO_CONNECTION;
 
         pbio_task_t *task;
@@ -2309,11 +2322,14 @@ PROCESS_THREAD(pbdrv_bluetooth_spi_process, ev, data) {
     for (;;) {
         PROCESS_WAIT_UNTIL({
             for (;;) {
-                if (observe_restart_enabled && etimer_expired(&observe_restart_timer)) {
+                if (observe_restart_requested && pbdrv_clock_get_ms() - observe_restart_time > OBSERVE_RESTART_INTERVAL) {
                     static pbio_task_t observe_restart_stop_task;
                     static pbio_task_t observe_restart_start_task;
                     pbdrv_bluetooth_start_observing_callback_t callback = observe_callback;
 
+                    // Avoid queueing this more than once.
+                    observe_restart_time = pbdrv_clock_get_ms();
+
                     pbdrv_bluetooth_stop_observing(&observe_restart_stop_task);
                     pbdrv_bluetooth_start_observing(&observe_restart_start_task, callback);
                 }

pybricks/common/pb_type_ble.c

@@ -440,6 +440,12 @@ static mp_obj_t pb_module_ble_observe(mp_obj_t self_in, mp_obj_t channel_in) {
 
     // Have not received data yet or timed out.
     if (ch_data.rssi == INT8_MIN) {
+
+        #if PBDRV_CONFIG_BLUETOOTH_STM32_CC2640
+        extern void pbdrv_bluetooth_restart_observing_request(void);
+        pbdrv_bluetooth_restart_observing_request();
+        #endif
+
         return mp_const_none;
     }