Index: sys/dev/sfxge/common/efx_vpd.c
===================================================================
--- sys/dev/sfxge/common/efx_vpd.c
+++ sys/dev/sfxge/common/efx_vpd.c
@@ -933,7 +933,7 @@
 		}
 
 		/* Modify tag length (large resource type) */
-		taglen += (dest - source);
+		taglen += (uint16_t)(dest - source);
 		EFX_POPULATE_WORD_1(word, EFX_WORD_0, taglen);
 		data[offset - 2] = EFX_WORD_FIELD(word, EFX_BYTE_0);
 		data[offset - 1] = EFX_WORD_FIELD(word, EFX_BYTE_1);