From 27a113ecab774c73a3fe26b99928a6ea6b06f5e5 Mon Sep 17 00:00:00 2001
From: Daniel Agar <daniel@agar.ca>
Date: Fri, 23 Apr 2021 13:38:29 -0400
Subject: [PATCH] parameters: param_get avoid locking if value is static
 default

---
 src/lib/parameters/parameters.cpp | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/lib/parameters/parameters.cpp b/src/lib/parameters/parameters.cpp
index 94f15b3a1d..add193b0cb 100644
--- a/src/lib/parameters/parameters.cpp
+++ b/src/lib/parameters/parameters.cpp
@@ -493,8 +493,20 @@ param_get(param_t param, void *val)
 	int result = PX4_ERROR;
 
 	if (val) {
-		param_lock_reader();
+		if (!params_changed[param] && !params_custom_default[param]) {
+			// if parameter is unchanged (static default value) copy immediately and avoid locking
+			switch (param_type(param)) {
+			case PARAM_TYPE_INT32:
+				memcpy(val, &px4::parameters[param].val.i, sizeof(px4::parameters[param].val.i));
+				return PX4_OK;
 
+			case PARAM_TYPE_FLOAT:
+				memcpy(val, &px4::parameters[param].val.f, sizeof(px4::parameters[param].val.f));
+				return PX4_OK;
+			}
+		}
+
+		param_lock_reader();
 		const void *v = param_get_value_ptr(param);
 
 		if (v) {