pm: prevent entering light sleep again immediately after wakeup

When light sleep is finished on one CPU, it is possible that the other
CPU will enter light sleep again very soon, before interrupts on the
first CPU get a chance to run. To avoid such situation, set a flag
for the other CPU to skip light sleep attempt.

diff --git a/components/esp32/pm_esp32.c b/components/esp32/pm_esp32.c
index b53ea079be82670dfe0aad750d9fe1e66dd8c2e3..0cf7e2d20d9a70f76a9a5b40a968b90c80a0aa6f 100644 (file)
--- a/components/esp32/pm_esp32.c
+++ b/components/esp32/pm_esp32.c
@@ -86,6 +86,15 @@ static uint32_t s_ccount_mul;
  * to be invoked or not.
  */
 static bool s_skipped_light_sleep[portNUM_PROCESSORS];
+
+#if portNUM_PROCESSORS == 2
+/* When light sleep is finished on one CPU, it is possible that the other CPU
+ * will enter light sleep again very soon, before interrupts on the first CPU
+ * get a chance to run. To avoid such situation, set a flag for the other CPU to
+ * skip light sleep attempt.
+ */
+static bool s_skip_light_sleep[portNUM_PROCESSORS];
+#endif // portNUM_PROCESSORS == 2
 #endif // CONFIG_FREERTOS_USE_TICKLESS_IDLE
 
 /* Indicates to the ISR hook that CCOMPARE needs to be updated on the given CPU.
@@ -481,14 +490,35 @@ void esp_pm_impl_waiti()
 
 #if CONFIG_FREERTOS_USE_TICKLESS_IDLE
 
-void IRAM_ATTR vApplicationSleep( TickType_t xExpectedIdleTime )
+static inline bool IRAM_ATTR should_skip_light_sleep(int core_id)
 {
-    portENTER_CRITICAL(&s_switch_lock);
-    int core_id = xPortGetCoreID();
+#if portNUM_PROCESSORS == 2
+    if (s_skip_light_sleep[core_id]) {
+        s_skip_light_sleep[core_id] = false;
+        s_skipped_light_sleep[core_id] = true;
+        return true;
+    }
+#endif // portNUM_PROCESSORS == 2
     if (s_mode != PM_MODE_LIGHT_SLEEP || s_is_switching) {
         s_skipped_light_sleep[core_id] = true;
     } else {
         s_skipped_light_sleep[core_id] = false;
+    }
+    return s_skipped_light_sleep[core_id];
+}
+
+static inline void IRAM_ATTR other_core_should_skip_light_sleep(int core_id)
+{
+#if portNUM_PROCESSORS == 2
+    s_skip_light_sleep[!core_id] = true;
+#endif
+}
+
+void IRAM_ATTR vApplicationSleep( TickType_t xExpectedIdleTime )
+{
+    portENTER_CRITICAL(&s_switch_lock);
+    int core_id = xPortGetCoreID();
+    if (!should_skip_light_sleep(core_id)) {
         /* Calculate how much we can sleep */
         int64_t next_esp_timer_alarm = esp_timer_get_next_alarm();
         int64_t now = esp_timer_get_time();
@@ -523,6 +553,7 @@ void IRAM_ATTR vApplicationSleep( TickType_t xExpectedIdleTime )
                     ;
                 }
             }
+            other_core_should_skip_light_sleep(core_id);
         }
     }
     portEXIT_CRITICAL(&s_switch_lock);