From 6670c2b6c422a1b9961a4484fbdc7d6a6589b5bf Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 9 Feb 2026 09:30:24 -0600
Subject: [PATCH] Add comment explaining early guard

---
 esphome/components/rd03d/rd03d.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/esphome/components/rd03d/rd03d.cpp b/esphome/components/rd03d/rd03d.cpp
index 1b3212e2c09..90ac87f93f2 100644
--- a/esphome/components/rd03d/rd03d.cpp
+++ b/esphome/components/rd03d/rd03d.cpp
@@ -81,6 +81,8 @@ void RD03DComponent::dump_config() {
 }
 
 void RD03DComponent::loop() {
+  // 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;