From f91ac5ed1d3226113957d912b265ca0915ae5c15 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 4 Oct 2026 21:20:56 -0500
Subject: [PATCH] [mipi_dsi] Keep the init sequence in flash (#20091)

---
 esphome/components/mipi_dsi/display.py            |  3 ++-
 esphome/components/mipi_dsi/mipi_dsi.cpp          | 15 ++++++++-------
 esphome/components/mipi_dsi/mipi_dsi.h            |  9 +++++++--
 .../mipi_dsi/test_mipi_dsi_config.py              |  8 +++++++-
 4 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/esphome/components/mipi_dsi/display.py b/esphome/components/mipi_dsi/display.py
index b23982655a..6bf94bf364 100644
--- a/esphome/components/mipi_dsi/display.py
+++ b/esphome/components/mipi_dsi/display.py
@@ -201,7 +201,8 @@ async def to_code(config: ConfigType) -> None:
 
     sequence = model.get_sequence(config)
     cg.add(var.set_model(config[CONF_MODEL]))
-    cg.add(var.set_init_sequence(sequence))
+    table = cg.shared_progmem_array("mipi_dsi_init_sequence", cg.uint8, sequence)
+    cg.add(var.set_init_sequence(table, len(sequence)))
     cg.add(var.set_invert_colors(config[CONF_INVERT_COLORS]))
     cg.add(var.set_hsync_pulse_width(config[CONF_HSYNC_PULSE_WIDTH]))
     cg.add(var.set_hsync_back_porch(config[CONF_HSYNC_BACK_PORCH]))
diff --git a/esphome/components/mipi_dsi/mipi_dsi.cpp b/esphome/components/mipi_dsi/mipi_dsi.cpp
index b6612038b6..a27be568f2 100644
--- a/esphome/components/mipi_dsi/mipi_dsi.cpp
+++ b/esphome/components/mipi_dsi/mipi_dsi.cpp
@@ -121,20 +121,21 @@ void MipiDsi::setup() {
     return;
   }
   size_t index = 0;
-  auto &vec = this->init_sequence_;
-  while (index != vec.size()) {
-    if (vec.size() - index < 2) {
+  const uint8_t *seq = this->init_sequence_;
+  const size_t len = this->init_sequence_len_;
+  while (index != len) {
+    if (len - index < 2) {
       this->mark_failed(LOG_STR("Malformed init sequence"));
       return;
     }
-    uint8_t cmd = vec[index++];
-    uint8_t x = vec[index++];
+    uint8_t cmd = seq[index++];
+    uint8_t x = seq[index++];
     if (x == DELAY_FLAG) {
       ESP_LOGD(TAG, "Delay %dms", cmd);
       delay(cmd);
     } else {
       uint8_t num_args = x & 0x7F;
-      if (vec.size() - index < num_args) {
+      if (len - index < num_args) {
         this->mark_failed(LOG_STR("Malformed init sequence"));
         return;
       }
@@ -145,7 +146,7 @@ void MipiDsi::setup() {
           delay(duration);
         }
       }
-      const auto *ptr = vec.data() + index;
+      const auto *ptr = seq + index;
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERY_VERBOSE
       char hex_buf[format_hex_pretty_size(MIPI_DSI_MAX_CMD_LOG_BYTES)];
 #endif
diff --git a/esphome/components/mipi_dsi/mipi_dsi.h b/esphome/components/mipi_dsi/mipi_dsi.h
index 7bf2feb73c..4243d3116c 100644
--- a/esphome/components/mipi_dsi/mipi_dsi.h
+++ b/esphome/components/mipi_dsi/mipi_dsi.h
@@ -55,7 +55,10 @@ class MipiDsi final : public display::Display {
   void set_vsync_pulse_width(uint16_t vsync_pulse_width) { this->vsync_pulse_width_ = vsync_pulse_width; }
   void set_vsync_back_porch(uint16_t vsync_back_porch) { this->vsync_back_porch_ = vsync_back_porch; }
   void set_vsync_front_porch(uint16_t vsync_front_porch) { this->vsync_front_porch_ = vsync_front_porch; }
-  void set_init_sequence(const std::vector<uint8_t> &init_sequence) { this->init_sequence_ = init_sequence; }
+  void set_init_sequence(const uint8_t *init_sequence, size_t len) {
+    this->init_sequence_ = init_sequence;
+    this->init_sequence_len_ = len;
+  }
   void set_model(const char *model) { this->model_ = model; }
   void set_lane_bit_rate(float lane_bit_rate) { this->lane_bit_rate_ = lane_bit_rate; }
   void set_lanes(uint8_t lanes) { this->lanes_ = lanes; }
@@ -91,7 +94,9 @@ class MipiDsi final : public display::Display {
   uint16_t vsync_back_porch_ = 10;
   uint16_t vsync_front_porch_ = 10;
   const char *model_{"Unknown"};
-  std::vector<uint8_t> init_sequence_{};
+  // Shared PROGMEM table
+  const uint8_t *init_sequence_{nullptr};
+  size_t init_sequence_len_{0};
   float pclk_frequency_ = 16;  // in MHz
   float lane_bit_rate_{1500};  // in Mbps
   uint8_t lanes_{2};           // 1, 2, 3 or 4 lanes
diff --git a/tests/component_tests/mipi_dsi/test_mipi_dsi_config.py b/tests/component_tests/mipi_dsi/test_mipi_dsi_config.py
index 6259d85184..ac385cc2d8 100644
--- a/tests/component_tests/mipi_dsi/test_mipi_dsi_config.py
+++ b/tests/component_tests/mipi_dsi/test_mipi_dsi_config.py
@@ -3,6 +3,7 @@
 from collections.abc import Callable
 import logging
 from pathlib import Path
+import re
 
 import pytest
 
@@ -201,7 +202,12 @@ def test_code_generation(
         "new(p4_nano) mipi_dsi::MipiDsi(800, 1280, display::COLOR_BITNESS_565, 16);"
         in main_cpp
     )
-    assert "set_init_sequence({224, 1, 0, 225, 1, 147, 226, 1," in main_cpp
+    seq = re.search(r"p4_nano->set_init_sequence\((\w+), \d+\);", main_cpp)
+    assert seq is not None
+    assert (
+        f"static constexpr uint8_t {seq.group(1)}[] PROGMEM = "
+        "{224, 1, 0, 225, 1, 147, 226, 1," in main_cpp
+    )
     assert "p4_nano->set_lane_bit_rate(1500.0f);" in main_cpp
     assert "p4_nano->set_rotation(display::DISPLAY_ROTATION_90_DEGREES);" in main_cpp
     assert "p4_86->set_rotation(display::DISPLAY_ROTATION_0_DEGREES);" not in main_cpp