Fixing Copilot findings

Author: ppsx

py/circuitpy_mpconfig.h

@@ -406,6 +406,13 @@ typedef long mp_off_t;
 #define CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE (512)
 #endif
 
+// Port-level upper bound for the QSPI display buffer (uint32_t words).
+// The _Static_assert in BusDisplay.c enforces this at compile time.
+// Ports with larger stacks can raise this in mpconfigport.h.
+#ifndef CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE_MAX
+#define CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE_MAX (2048)
+#endif
+
 #else
 #define CIRCUITPY_DISPLAY_LIMIT (0)
 #define CIRCUITPY_DISPLAY_AREA_BUFFER_SIZE (0)

shared-module/busdisplay/BusDisplay.c

@@ -261,10 +261,10 @@ static bool _refresh_area(busdisplay_busdisplay_obj_t *self, const displayio_are
     // QSPI panels benefit from larger sub-rectangle buffers because each chunk
     // has non-trivial command/window overhead. Keep this path qspibus-specific
     // to avoid increasing stack usage on other display buses.
-    // Guard: buffer is a VLA on stack; 2048 uint32_t words = 8KB is the safe
-    // upper bound for ESP32-S3's 24KB main task stack.
-    _Static_assert(CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE <= 2048,
-        "CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE exceeds safe stack limit (8KB)");
+    // Guard: buffer is a VLA on stack. The port-specific max keeps shared
+    // code free of single-port assumptions (default 2048 words = 8KB).
+    _Static_assert(CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE <= CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE_MAX,
+        "CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE exceeds CIRCUITPY_QSPI_DISPLAY_AREA_BUFFER_SIZE_MAX");
     bool is_qspi_bus = mp_obj_is_type(self->bus.bus, &qspibus_qspibus_type);
     if (is_qspi_bus &&
         self->core.colorspace.depth == 16 &&