fix(ble/bluedroid): allow osi_event re-post during POSTING window

Do not reject osi_thread_post_event() when only POSTING is set.
QUEUED already prevents double-queueing; rejecting POSTING caused
HCI downstream lost wakeup. Add generic osi_event and hci downstream
diagnostics for post failures.

components/bt/common/osi/thread.c

@@ -534,13 +534,30 @@ static bool osi_event_can_bind_locked(const struct osi_event *event, osi_thread_
 static bool osi_event_can_post_locked(const struct osi_event *event)
 {
     if (event->thread == NULL || event->queue_idx >= event->thread->work_queue_num) {
+        OSI_TRACE_EVENT("%s deny ev=%p flags=0x%x qidx=%u",
+                        __func__, event, event ? event->flags : 0,
+                        event ? event->queue_idx : 0);
         return false;
     }
 
-    return !OSI_EVENT_HAS_FLAG(event, OSI_EVENT_FLAG_DELETING) &&
-           event->item.func != NULL &&
-           !OSI_EVENT_HAS_FLAG(event, OSI_EVENT_FLAG_QUEUED) &&
-           !OSI_EVENT_HAS_FLAG(event, OSI_EVENT_FLAG_POSTING);
+    if (OSI_EVENT_HAS_FLAG(event, OSI_EVENT_FLAG_DELETING) ||
+            event->item.func == NULL ||
+            OSI_EVENT_HAS_FLAG(event, OSI_EVENT_FLAG_QUEUED)) {
+        OSI_TRACE_EVENT("%s deny ev=%p flags=0x%x qidx=%u wq_len=%d",
+                        __func__, event, event->flags, event->queue_idx,
+                        osi_thread_queue_wait_size(event->thread, event->queue_idx));
+        return false;
+    }
+
+    /* Do NOT gate on OSI_EVENT_FLAG_POSTING here. POSTING marks the window in
+     * osi_thread_post_event() between osi_thread_post() (enqueue) and the
+     * poster clearing the flag. During that window the generic event handler
+     * may already have run and cleared QUEUED. A concurrent post that arrives
+     * after QUEUED is cleared is a legitimate re-post (new work arrived while
+     * the handler was draining) and must be accepted; rejecting it causes a
+     * lost wakeup. QUEUED alone prevents genuine double-queueing. POSTING is
+     * retained only for osi_event_is_idle()/osi_event_should_free(). */
+    return true;
 }
 
 static bool osi_event_is_alive_locked(const struct osi_event *event)
@@ -714,6 +731,7 @@ static void osi_thread_generic_event_handler(void *context)
     OSI_EVENT_SET_FLAG(event, OSI_EVENT_FLAG_RUNNING);
     func = event->item.func;
     func_context = event->item.context;
+    OSI_TRACE_DEBUG("%s enter ev=%p flags=0x%x", __func__, event, event->flags);
     osi_mutex_unlock(&event->lock);
 
     if (func != NULL) {
@@ -722,6 +740,7 @@ static void osi_thread_generic_event_handler(void *context)
 
     osi_mutex_lock(&event->lock, OSI_MUTEX_MAX_TIMEOUT);
     OSI_EVENT_CLEAR_FLAG(event, OSI_EVENT_FLAG_RUNNING);
+    OSI_TRACE_DEBUG("%s exit ev=%p flags=0x%x", __func__, event, event->flags);
     osi_mutex_unlock(&event->lock);
 
     osi_event_release(event);
@@ -755,6 +774,7 @@ bool osi_thread_post_event(struct osi_event *event, uint32_t timeout)
     uint8_t queue_idx = 0;
 
     if (!osi_event_acquire(event)) {
+        OSI_TRACE_EVENT("%s acquire fail ev=%p", __func__, event);
         return false;
     }
 
@@ -782,6 +802,9 @@ bool osi_thread_post_event(struct osi_event *event, uint32_t timeout)
     osi_mutex_unlock(&event->lock);
 
     if (!ret) {
+        OSI_TRACE_EVENT("%s enqueue fail ev=%p qidx=%u wq_len=%d",
+                        __func__, event, queue_idx,
+                        osi_thread_queue_wait_size(thread, queue_idx));
         osi_event_release(event);
     }
     osi_event_release(event);

components/bt/host/bluedroid/hci/hci_layer.c

@@ -155,11 +155,21 @@ void hci_shut_down(void)
 
 bool hci_downstream_data_post(uint32_t timeout)
 {
+    bool ret;
+
     if (hci_host_env.downstream_data_ready == NULL) {
         HCI_TRACE_WARNING("%s downstream_data_ready event not created", __func__);
         return false;
     }
-    return osi_thread_post_event(hci_host_env.downstream_data_ready, timeout);
+
+    ret = osi_thread_post_event(hci_host_env.downstream_data_ready, timeout);
+    if (!ret) {
+        HCI_TRACE_DEBUG("%s post fail credits=%d cmdq=%u pktq=%u",
+                        __func__, hci_host_env.command_credits,
+                        (unsigned)fixed_pkt_queue_length(hci_host_env.command_queue),
+                        (unsigned)fixed_queue_length(hci_host_env.packet_queue));
+    }
+    return ret;
 }
 
 static int hci_layer_init_env(void)
@@ -249,6 +259,8 @@ static void hci_downstream_data_handler(void *arg)
      * All packets will be directly copied to single queue in driver layer with
      * H4 type header added (1 byte).
      */
+    UNUSED(arg);
+
     while (hci_host_check_send_available()) {
         /*Now Target only allowed one packet per TX*/
         BT_HDR *pkt = packet_fragmenter->fragment_current_packet();
@@ -264,6 +276,11 @@ static void hci_downstream_data_handler(void *arg)
             break;
         }
     }
+
+    HCI_TRACE_DEBUG("%s done credits=%d cmdq=%u pktq=%u",
+                    __func__, hci_host_env.command_credits,
+                    (unsigned)fixed_pkt_queue_length(hci_host_env.command_queue),
+                    (unsigned)fixed_queue_length(hci_host_env.packet_queue));
 }
 
 static void transmit_command(