Index: sys/cam/mmc/mmc_da.c
===================================================================
--- sys/cam/mmc/mmc_da.c
+++ sys/cam/mmc/mmc_da.c
@@ -238,7 +238,9 @@
 mmc_handle_reply(union ccb *ccb)
 {
 
-	KASSERT(ccb->ccb_h.func_code == XPT_MMC_IO, ("cannot handle non-XPT_MMC_IO errors"));
+	KASSERT(ccb->ccb_h.func_code == XPT_MMC_IO,
+	    ("ccb %p: cannot handle non-XPT_MMC_IO errors, got func_code=%d",
+		ccb, ccb->ccb_h.func_code));
 
 	/* TODO: maybe put MMC-specific handling into cam.c/cam_error_print altogether */
 	if (((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP)) {