Document new parameter + pre-commit

Author: RetiredWizard

docs/environment.rst

@@ -190,3 +190,27 @@ flag has been set to 0. Currently this is primarily boards with limited flash in
 of the Atmel_samd boards based on the SAMD21/M0 microprocessor.
 
 `boards that the terminalio core module is available on <https://docs.circuitpython.org/en/latest/shared-bindings/terminalio/>`_
+
+CIRCUITPY_DISPLAY_LIMIT
+~~~~~~~~~~~~~~~~~~~~~~~
+Set the maximum supported number of displayio displays. This value overrides the
+CIRCUITPY_DISPLAY_LIMIT compile-time flag defined in mpconfigport.h.
+It specifies the maximum number of active display objects that can be supported simultaneously
+on a CircuitPython board. This setting is used to manage memory and resource allocation for
+display handling.
+
+By default, the value of CIRCUITPY_DISPLAY_LIMIT is set to 1 for most boards, meaning only
+one display can be active at a time. Users can modify this value by adding a settings.toml entry
+to support additional displays, depending on the hardware capabilities and available resources.
+
+The value of CIRCUITPY_DISPLAY_LIMIT should be set to a value that is supported by the
+hardware and does not exceed the available memory and resources on the board.
+
+*** Note: Setting CIRCUITPY_DISPLAY_LIMIT to a value greater than 1 should be considered an
+ALPHA feature and may result in unexpected behavior or crashes. ***
+
+Example: Set the maximum supported number of displayio displays to 2:
+
+.. code-block::
+
+    CIRCUITPY_DISPLAY_LIMIT=2

main.c

@@ -1058,7 +1058,7 @@ int __attribute__((used)) main(void) {
     reset_board();
 
     #if CIRCUITPY_DISPLAYIO
-    // If number of displays has been overriden in settings.toml allocate memory and dynamic memory
+    // If number of displays has been overridden in settings.toml allocate memory and dynamic memory
     malloc_display_memory();
     #endif
 

shared-module/displayio/__init__.c

@@ -201,10 +201,10 @@ void malloc_display_memory(void) {
     #if CIRCUITPY_OS_GETENV
     (void)common_hal_os_getenv_int("CIRCUITPY_DISPLAY_LIMIT", &max_num_displays);
     if (max_num_displays > CIRCUITPY_DISPLAY_LIMIT) {
-        display_buses = (primary_display_bus_t*)port_malloc(sizeof(primary_display_bus_t) * max_num_displays, false);
-        displays = (primary_display_t*)port_malloc(sizeof(primary_display_t) * max_num_displays, false);
+        display_buses = (primary_display_bus_t *)port_malloc(sizeof(primary_display_bus_t) * max_num_displays, false);
+        displays = (primary_display_t *)port_malloc(sizeof(primary_display_t) * max_num_displays, false);
         memcpy(display_buses, &display_busesx[0], sizeof(primary_display_bus_t) * max_num_displays);
-        memcpy(displays, &displaysx[0], sizeof(primary_display_t) * max_num_displays);    
+        memcpy(displays, &displaysx[0], sizeof(primary_display_t) * max_num_displays);
     }
     #endif
 }