From 4cb5ab4a039aceccd450eb901e7dfc4b4cf57fa2 Mon Sep 17 00:00:00 2001
From: Themba Dube <embeddedthemba@gmail.com>
Date: Tue, 10 Dec 2019 20:09:40 -0500
Subject: [PATCH] Suspend the refresh task if a refresh is not necessary

---
 src/lv_core/lv_refr.c    | 8 ++++++++
 src/lv_core/lv_refr.h    | 2 ++
 src/lv_hal/lv_hal_disp.c | 2 +-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/lv_core/lv_refr.c b/src/lv_core/lv_refr.c
index d8d4ce6c0..141ac5a07 100644
--- a/src/lv_core/lv_refr.c
+++ b/src/lv_core/lv_refr.c
@@ -131,6 +131,8 @@ void lv_inv_area(lv_disp_t * disp, const lv_area_t * area_p)
             lv_area_copy(&disp->inv_areas[disp->inv_p], &scr_area);
         }
         disp->inv_p++;
+		lv_task_set_prio(disp->refr_task, LV_REFR_TASK_PRIO);
+		dprintf("refr task enabled\n");
     }
 }
 
@@ -164,6 +166,12 @@ void lv_disp_refr_task(lv_task_t * task)
 
     uint32_t start = lv_tick_get();
 
+	/* Ensure the task does not run again automatically.
+     * This is done before refreshing in case refreshing invalidates something else.
+     */
+	lv_task_set_prio(task, LV_TASK_PRIO_OFF);
+	dprintf("refr task disabled\n");
+
     disp_refr = task->user_data;
 
     lv_refr_join_area();
diff --git a/src/lv_core/lv_refr.h b/src/lv_core/lv_refr.h
index 8c0ed03ed..35f2791c8 100644
--- a/src/lv_core/lv_refr.h
+++ b/src/lv_core/lv_refr.h
@@ -20,6 +20,8 @@ extern "C" {
  *      DEFINES
  *********************/
 
+#define LV_REFR_TASK_PRIO LV_TASK_PRIO_MID
+
 /**********************
  *      TYPEDEFS
  **********************/
diff --git a/src/lv_hal/lv_hal_disp.c b/src/lv_hal/lv_hal_disp.c
index 11a3bbcb2..db5461447 100644
--- a/src/lv_hal/lv_hal_disp.c
+++ b/src/lv_hal/lv_hal_disp.c
@@ -147,7 +147,7 @@ lv_disp_t * lv_disp_drv_register(lv_disp_drv_t * driver)
     disp_def = disp_def_tmp; /*Revert the default display*/
 
     /*Create a refresh task*/
-    disp->refr_task = lv_task_create(lv_disp_refr_task, LV_DISP_DEF_REFR_PERIOD, LV_TASK_PRIO_MID, disp);
+    disp->refr_task = lv_task_create(lv_disp_refr_task, LV_DISP_DEF_REFR_PERIOD, LV_REFR_TASK_PRIO, disp);
     LV_ASSERT_MEM(disp->refr_task);
     if(disp->refr_task == NULL) return NULL;