diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index 9a42a08c8ed5..9f3e3d37e82a 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -481,6 +481,9 @@ static int lynxfb_ops_check_var(struct fb_var_screeninfo *var,
 	struct lynxfb_crtc *crtc;
 	resource_size_t request;
 
+	if (!var->pixclock)
+		return -EINVAL;
+
 	ret = 0;
 	par = info->par;
 	crtc = &par->crtc;