pbio/sys/status: Handle status change synchronously.

This was using broadcast, but there was ultimately only one receiver for this data. We can simplify this and avoid the risk of overrunning the event queue by calling it synchronously, which is safe for this event.

After the refactoring in the previous commit, this is now a trivial change.

Author: laurensvalk

lib/pbio/sys/core.c

@@ -30,7 +30,7 @@ PROCESS_THREAD(pbsys_system_process, ev, data) {
 
     for (;;) {
         PROCESS_WAIT_EVENT();
-        pbsys_hmi_handle_status_change((pbsys_status_change_t)ev, (pbio_pybricks_status_t)data);
+
         if (ev == PROCESS_EVENT_TIMER && etimer_expired(&timer)) {
             etimer_reset(&timer);
             pbsys_battery_poll();

lib/pbio/sys/status.c

@@ -12,6 +12,8 @@
 #include <pbdrv/clock.h>
 #include <pbsys/status.h>
 
+#include "hmi.h"
+
 static struct {
     /** Status indications as bit flags */
     uint32_t flags;
@@ -31,9 +33,11 @@ static void pbsys_status_update_flag(pbio_pybricks_status_t status, bool set) {
 
     pbsys_status.flags = new_flags;
     pbsys_status.changed_time[status] = pbdrv_clock_get_ms();
-    // REVISIT: this can drop events if event queue is full
-    process_post(PROCESS_BROADCAST, set ? PBSYS_STATUS_CHANGE_SET : PBSYS_STATUS_CHANGE_CLEARED,
-        (process_data_t)status);
+
+    // hmi is the only subscriber to status changes, so call its handler
+    // directly. All other processes just poll the status as needed. If we ever
+    // need more subscribers, we could register callbacks and call them here.
+    pbsys_hmi_handle_status_change(set ? PBSYS_STATUS_CHANGE_SET : PBSYS_STATUS_CHANGE_CLEARED, status);
 }
 
 /**