diff --git a/src/vulkan/wsi/wsi_common_x11.c b/src/vulkan/wsi/wsi_common_x11.c
index b5832c685e6..548352eec24 100644
--- a/src/vulkan/wsi/wsi_common_x11.c
+++ b/src/vulkan/wsi/wsi_common_x11.c
@@ -394,11 +394,16 @@ x11_surface_get_formats(VkIcdSurfaceBase *surface,
       return VK_SUCCESS;
    }
 
-   assert(*pSurfaceFormatCount >= ARRAY_SIZE(formats));
-   typed_memcpy(pSurfaceFormats, formats, *pSurfaceFormatCount);
-   *pSurfaceFormatCount = ARRAY_SIZE(formats);
+   VkResult result = VK_SUCCESS;
 
-   return VK_SUCCESS;
+   if (*pSurfaceFormatCount > ARRAY_SIZE(formats))
+      *pSurfaceFormatCount = ARRAY_SIZE(formats);
+   else if (*pSurfaceFormatCount < ARRAY_SIZE(formats))
+      result = VK_INCOMPLETE;
+
+   typed_memcpy(pSurfaceFormats, formats, *pSurfaceFormatCount);
+
+   return result;
 }
 
 static VkResult