diff --git a/sys/dev/drm/amd/display/dc/gpio/diagnostics/hw_translate_diag.c b/sys/dev/drm/amd/display/dc/gpio/diagnostics/hw_translate_diag.c
index 000000000000..000000000000 100644
--- a/sys/dev/drm/amd/display/dc/gpio/diagnostics/hw_translate_diag.c
+++ b/sys/dev/drm/amd/display/dc/gpio/diagnostics/hw_translate_diag.c
@@ -30,12 +30,27 @@

 #include "hw_translate_diag.h"

+/*
+ * Stub translators: the FPGA MAXIMUS environment has no GPIO register
+ * translation. Returning false (instead of leaving NULL function pointers)
+ * makes dal_gpio_service_create_*() fail cleanly with ASSERT_CRITICAL /
+ * GPIO_RESULT_INVALID_DATA rather than calling through a NULL pointer.
+ */
+static bool offset_to_id(
+	uint32_t offset,
+	uint32_t mask,
+	enum gpio_id *id,
+	uint32_t *en)
+{
+	return false;
+}
+
+static bool id_to_offset(
+	enum gpio_id id,
+	uint32_t en,
+	struct gpio_pin_info *info)
+{
+	return false;
+}
+
 /* function table */
 static const struct hw_translate_funcs funcs = {
-	.offset_to_id = NULL,
-	.id_to_offset = NULL,
+	.offset_to_id = offset_to_id,
+	.id_to_offset = id_to_offset,
 };

 void dal_hw_translate_diag_fpga_init(struct hw_translate *tr)