Use compile-time arrays AND additional dynamic memory

Author: RetiredWizard

main.c

@@ -1051,7 +1051,7 @@ int __attribute__((used)) main(void) {
     alarm_reset();
     #endif
 
-    #if CIRCUITPY_DISPLAYIO
+    #if CIRCUITPY_DISPLAYIO && CIRCUITPY_OS_GETENV
     // If number of displays has been overridden in settings.toml allocate memory and
     // move existing displays
     malloc_display_memory();

shared-module/board/__init__.c

@@ -178,18 +178,23 @@ mp_obj_t common_hal_board_create_uart(const mp_int_t instance) {
 void reset_board_buses(void) {
     #if CIRCUITPY_BOARD_I2C || (CIRCUITPY_BOARD_SPI && (CIRCUITPY_FOURWIRE || CIRCUITPY_SHARPDISPLAY || CIRCUITPY_AURORA_EPAPER))
     mp_int_t max_num_displays = CIRCUITPY_DISPLAY_LIMIT;
+    #if CIRCUITPY_OS_GETENV
+    #define DYN_DISPLAY_BUSES(indx) (indx < CIRCUITPY_DISPLAY_LIMIT ? display_buses[indx] : display_buses_dyn[indx - CIRCUITPY_DISPLAY_LIMIT])
+    #else
+    #define DYN_DISPLAY_BUSES(indx) (display_buses[indx])
+    #endif
 
     #if CIRCUITPY_OS_GETENV
     (void)common_hal_os_getenv_int("CIRCUITPY_DISPLAY_LIMIT", &max_num_displays);
     #endif
     #endif
 
     #if CIRCUITPY_BOARD_I2C
-    for (uint8_t instance = 0; instance < max_num_displays; instance++) {
+    for (uint8_t instance = 0; instance < CIRCUITPY_BOARD_I2C; instance++) {
         bool display_using_i2c = false;
         #if CIRCUITPY_I2CDISPLAYBUS
         for (uint8_t i = 0; i < max_num_displays; i++) {
-            if (display_buses[i].bus_base.type == &i2cdisplaybus_i2cdisplaybus_type && display_buses[i].i2cdisplay_bus.bus == &i2c_obj[instance]) {
+            if (DYN_DISPLAY_BUSES(i).bus_base.type == &i2cdisplaybus_i2cdisplaybus_type && DYN_DISPLAY_BUSES(i).i2cdisplay_bus.bus == &i2c_obj[instance]) {
                 display_using_i2c = true;
                 break;
             }
@@ -210,21 +215,21 @@ void reset_board_buses(void) {
         bool display_using_spi = false;
         #if CIRCUITPY_FOURWIRE || CIRCUITPY_SHARPDISPLAY || CIRCUITPY_AURORA_EPAPER
         for (uint8_t i = 0; i < max_num_displays; i++) {
-            mp_const_obj_t bus_type = display_buses[i].bus_base.type;
+            mp_const_obj_t bus_type = DYN_DISPLAY_BUSES(i).bus_base.type;
             #if CIRCUITPY_FOURWIRE
-            if (bus_type == &fourwire_fourwire_type && display_buses[i].fourwire_bus.bus == &spi_obj[instance]) {
+            if (bus_type == &fourwire_fourwire_type && DYN_DISPLAY_BUSES(i).fourwire_bus.bus == &spi_obj[instance]) {
                 display_using_spi = true;
                 break;
             }
             #endif
             #if CIRCUITPY_SHARPDISPLAY
-            if (bus_type == &sharpdisplay_framebuffer_type && display_buses[i].sharpdisplay.bus == &spi_obj[instance]) {
+            if (bus_type == &sharpdisplay_framebuffer_type && DYN_DISPLAY_BUSES(i).sharpdisplay.bus == &spi_obj[instance]) {
                 display_using_spi = true;
                 break;
             }
             #endif
             #if CIRCUITPY_AURORA_EPAPER
-            if (bus_type == &aurora_epaper_framebuffer_type && display_buses[i].aurora_epaper.bus == &spi_obj[instance]) {
+            if (bus_type == &aurora_epaper_framebuffer_type && DYN_DISPLAY_BUSES(i).aurora_epaper.bus == &spi_obj[instance]) {
                 display_using_spi = true;
                 break;
             }