diff --git a/drivers/video/fbmon.c b/drivers/video/fbmon.c
index 6a0aa180c266e0b3d03e8cc2a4dc890f1605d329..5c1a2c01778fe6e195df9405d0409d7a1a2a09f9 100644
--- a/drivers/video/fbmon.c
+++ b/drivers/video/fbmon.c
@@ -564,7 +564,13 @@ static void get_detailed_timing(unsigned char *block,
 		mode->sync |= FB_SYNC_VERT_HIGH_ACT;
 	mode->refresh = PIXEL_CLOCK/((H_ACTIVE + H_BLANKING) *
 				     (V_ACTIVE + V_BLANKING));
-	mode->vmode = 0;
+	if (INTERLACED) {
+		mode->yres *= 2;
+		mode->upper_margin *= 2;
+		mode->lower_margin *= 2;
+		mode->vsync_len *= 2;
+		mode->vmode |= FB_VMODE_INTERLACED;
+	}
 	mode->flag = FB_MODE_IS_DETAILED;
 
 	DPRINTK("      %d MHz ",  PIXEL_CLOCK/1000000);