From 1f1405364dc6a7fbee7c5ad6d5cf7af168b72bc0 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 9 Feb 2026 09:29:25 -0600
Subject: [PATCH] Add comment explaining early guard

---
 esphome/components/ld2420/ld2420.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/esphome/components/ld2420/ld2420.cpp b/esphome/components/ld2420/ld2420.cpp
index f775876f594..253599fadb4 100644
--- a/esphome/components/ld2420/ld2420.cpp
+++ b/esphome/components/ld2420/ld2420.cpp
@@ -541,6 +541,8 @@ void LD2420Component::handle_simple_mode_(const uint8_t *inbuf, int len) {
 }
 
 void LD2420Component::read_batch_(std::span<uint8_t, MAX_LINE_LENGTH> buffer) {
+  // Early return avoids stack adjustment for the batch buffer below.
+  // loop() runs ~7000/min so most calls have nothing to read.
   int avail = this->available();
   if (avail <= 0) {
     return;