diff --git a/drivers/video/aty/radeon_monitor.c b/drivers/video/aty/radeon_monitor.c
index 7f9838d..98c05bc 100644
--- a/drivers/video/aty/radeon_monitor.c
+++ b/drivers/video/aty/radeon_monitor.c
@@ -396,6 +396,10 @@
 				s1[i] = *s;
 			i++;
 		}
+
+		if (i > 4)
+			i = 4;
+
 	} while (*s++);
 	if (second)
 		s2[i] = 0;