diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index 12bd5a7318e1..7b221164dd95 100644
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -1077,6 +1077,9 @@ static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
 	struct fb_videomode mode;
 	struct dlfb_data *dlfb = info->par;
 
+	if (!var->pixclock)
+		return -EINVAL;
+
 	/* set device-specific elements of var unrelated to mode */
 	dlfb_var_color_format(var);