[il9xxx] Add notes about psram and 8 bit changes (#4699)

Author: clydebarrow

changelog/2025.2.0.rst

@@ -106,6 +106,19 @@ from a boolean to an enum; in addition, the ``type`` configuration variable is n
 
 Finally, the :doc:`/components/online_image` was updated to add support for both BMP and JPEG image formats.
 
+ILI9XXX Display Component
+-------------------------
+
+There are two changes to the :doc:`/components/display/ili9xxx` component. Previously the component automatically loaded
+the ``psram`` component - this has been removed, and you must now explicitly include the
+``psram`` component in your configuration if your display requires it. The bit-depth defaults to 16 bit as before, but
+there is no attempt to automatically fallback to 8 bit if insufficient memory is available. You must now explicitly
+select 8-bit mode with the ``color_palette`` configuration variable if required.
+
+The symptoms caused by these changes are likely to be a blank screen or a screen that is not displaying correctly. Check
+the runtime logs for any errors or warnings that may indicate the cause of the issue, specifically memory allocation
+failures.
+
 Full list of changes
 --------------------
 

components/display/ili9xxx.rst

@@ -42,9 +42,14 @@ beyond the basic SPI connections, and a reasonable amount of RAM, it is not well
 
 .. note::
 
-    The default color depth is 16 bit (RGB565). 8 bit color is also supported, but the color palette must be set to one of the available options.
+    PSRAM is not automatically enabled on the ESP32 (this changed with the 2025.2 release.) If PSRAM is available, you
+    should enable it with the :doc:`PSRAM configuration </components/psram>`.
     Use of 16 bit colors requires twice the amount of RAM as 8 bit, and may not be usable unless PSRAM is available.
 
+.. note::
+
+    The default color depth is 16 bit (RGB565). 8 bit color is also supported, but the color palette must be set to one of the available options.
+    Use of 16 bit colors requires twice the amount of RAM as 8 bit, and may not be usable unless PSRAM is available.
 
 .. figure:: images/ili9341-full.jpg
     :align: center