diff --git a/src/surface.c b/src/surface.c
index 2a55b08..f2df393 100644
--- a/src/surface.c
+++ b/src/surface.c
@@ -146,6 +146,23 @@ VAStatus RequestCreateSurfaces2(VADriverContextP context, unsigned int format,
 
 	destination_planes_count = video_format->planes_count;
 
+	/*
+	 * DEBUG INSTRUMENTATION (surface-export diagnosis 2026-05-04):
+	 * dump what v4l2_get_format returned. Sonnet's Phase 5 review
+	 * hypothesis #4 was that format_height might be 1080 (stream-
+	 * signaled) vs 1088 (MB-aligned), causing UV offset to land
+	 * 15360 bytes early. Earlier ftrace shows hantro returns
+	 * height=1088 — but verify in-driver to be sure.
+	 */
+	request_log("CreateSurfaces2: surf_width=%u surf_height=%u "
+		    "fmt_width=%u fmt_height=%u bytesperline[0]=%u "
+		    "sizes[0]=%u sizes[1]=%u planes_count=%u "
+		    "v4l2_buffers_count=%u\n",
+		    width, height, format_width, format_height,
+		    destination_bytesperlines[0],
+		    destination_sizes[0], destination_sizes[1],
+		    destination_planes_count, video_format->v4l2_buffers_count);
+
 	rc = v4l2_create_buffers(driver_data->video_fd, capture_type,
 				 surfaces_count, &index_base);
 	if (rc < 0)
@@ -619,6 +636,33 @@ VAStatus RequestExportSurfaceHandle(VADriverContextP context,
 			surface_object->destination_bytesperlines[i];
 	}
 
+	/*
+	 * DEBUG INSTRUMENTATION (surface-export diagnosis 2026-05-04):
+	 * dump the full descriptor so we can compare against what mpv
+	 * reports importing via --msg-level=vd=v --msg-level=vo=v.
+	 * Phase 5 review identified DMA-BUF surface export as the
+	 * likely root cause of the solid-blue render in mpv vaapi mode.
+	 */
+	request_log("ExportSurfaceHandle: surf=%u fd[0]=%d fourcc=0x%x "
+		    "w=%u h=%u num_objects=%u num_layers=%u "
+		    "obj[0].size=%u drm_fmt=0x%x drm_mod=0x%llx num_planes=%u "
+		    "p[0].off=%u pitch=%u  p[1].off=%u pitch=%u\n",
+		    surface_id,
+		    export_fds_count > 0 ? export_fds[0] : -1,
+		    surface_descriptor->fourcc,
+		    surface_descriptor->width,
+		    surface_descriptor->height,
+		    surface_descriptor->num_objects,
+		    surface_descriptor->num_layers,
+		    surface_descriptor->objects[0].size,
+		    surface_descriptor->layers[0].drm_format,
+		    (unsigned long long)surface_descriptor->objects[0].drm_format_modifier,
+		    surface_descriptor->layers[0].num_planes,
+		    surface_descriptor->layers[0].offset[0],
+		    surface_descriptor->layers[0].pitch[0],
+		    planes_count > 1 ? surface_descriptor->layers[0].offset[1] : 0,
+		    planes_count > 1 ? surface_descriptor->layers[0].pitch[1] : 0);
+
 	status = VA_STATUS_SUCCESS;
 	goto complete;