diff --git a/drivers/gpu/drm/amd/display/dmub/inc/dmub_rb.h b/drivers/gpu/drm/amd/display/dmub/inc/dmub_rb.h
index ac22744eaa94..ade688fd32f0 100644
--- a/drivers/gpu/drm/amd/display/dmub/inc/dmub_rb.h
+++ b/drivers/gpu/drm/amd/display/dmub/inc/dmub_rb.h
@@ -113,6 +113,23 @@ static inline bool dmub_rb_pop_front(struct dmub_rb *rb)
 	return true;
 }
 
+static inline void dmub_rb_flush_pending(const struct dmub_rb *rb)
+{
+	uint8_t buf[DMUB_RB_CMD_SIZE];
+	uint32_t rptr = rb->rptr;
+	uint32_t wptr = rb->wrpt;
+
+	while (rptr != wptr) {
+		const uint8_t *data = (const uint8_t *)rb->base_address + rptr;
+
+		dmub_memcpy(buf, data, DMUB_RB_CMD_SIZE);
+
+		rptr += DMUB_RB_CMD_SIZE;
+		if (rptr >= rb->capacity)
+			rptr %= rb->capacity;
+	}
+}
+
 static inline void dmub_rb_init(struct dmub_rb *rb,
 				struct dmub_rb_init_params *init_params)
 {
diff --git a/drivers/gpu/drm/amd/display/dmub/inc/dmub_srv.h b/drivers/gpu/drm/amd/display/dmub/inc/dmub_srv.h
index f34a50dd36ea..8e23a7017588 100644
--- a/drivers/gpu/drm/amd/display/dmub/inc/dmub_srv.h
+++ b/drivers/gpu/drm/amd/display/dmub/inc/dmub_srv.h
@@ -444,25 +444,6 @@ enum dmub_status dmub_srv_cmd_queue(struct dmub_srv *dmub,
  */
 enum dmub_status dmub_srv_cmd_execute(struct dmub_srv *dmub);
 
-/**
- * dmub_srv_cmd_submit() - submits a command to the DMUB immediately
- * @dmub: the dmub service
- * @cmd: the command to submit
- * @timeout_us: the maximum number of microseconds to wait
- *
- * Submits a command to the DMUB with an optional timeout.
- * If timeout_us is given then the service will attempt to
- * resubmit for the given number of microseconds.
- *
- * Return:
- *   DMUB_STATUS_OK - success
- *   DMUB_STATUS_TIMEOUT - wait for submit timed out
- *   DMUB_STATUS_INVALID - unspecified error
- */
-enum dmub_status dmub_srv_cmd_submit(struct dmub_srv *dmub,
-				     const struct dmub_cmd_header *cmd,
-				     uint32_t timeout_us);
-
 /**
  * dmub_srv_wait_for_auto_load() - Waits for firmware auto load to complete
  * @dmub: the dmub service
diff --git a/drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c b/drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c
index 9a959f871f11..23ca1fe97757 100644
--- a/drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c
@@ -405,33 +405,17 @@ enum dmub_status dmub_srv_cmd_execute(struct dmub_srv *dmub)
 	if (!dmub->hw_init)
 		return DMUB_STATUS_INVALID;
 
+	/**
+	 * Read back all the queued commands to ensure that they've
+	 * been flushed to framebuffer memory. Otherwise DMCUB might
+	 * read back stale, fully invalid or partially invalid data.
+	 */
+	dmub_rb_flush_pending(&dmub->inbox1_rb);
+
 	dmub->hw_funcs.set_inbox1_wptr(dmub, dmub->inbox1_rb.wrpt);
 	return DMUB_STATUS_OK;
 }
 
-enum dmub_status dmub_srv_cmd_submit(struct dmub_srv *dmub,
-				     const struct dmub_cmd_header *cmd,
-				     uint32_t timeout_us)
-{
-	uint32_t i = 0;
-
-	if (!dmub->hw_init)
-		return DMUB_STATUS_INVALID;
-
-	for (i = 0; i <= timeout_us; ++i) {
-		dmub->inbox1_rb.rptr = dmub->hw_funcs.get_inbox1_rptr(dmub);
-		if (dmub_rb_push_front(&dmub->inbox1_rb, cmd)) {
-			dmub->hw_funcs.set_inbox1_wptr(dmub,
-						       dmub->inbox1_rb.wrpt);
-			return DMUB_STATUS_OK;
-		}
-
-		udelay(1);
-	}
-
-	return DMUB_STATUS_TIMEOUT;
-}
-
 enum dmub_status dmub_srv_wait_for_auto_load(struct dmub_srv *dmub,
 					     uint32_t timeout_us)
 {