diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 173b7d3..f64ac86 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -165,6 +165,7 @@
 	unsigned int vfieldrate, hperiod;
 	int hdisplay_rnd, hmargin, vdisplay_rnd, vmargin, vsync;
 	int interlace;
+	u64 tmp;
 
 	/* allocate the drm_display_mode structure. If failure, we will
 	 * return directly
@@ -322,8 +323,11 @@
 		drm_mode->vsync_end = drm_mode->vsync_start + vsync;
 	}
 	/* 15/13. Find pixel clock frequency (kHz for xf86) */
-	drm_mode->clock = drm_mode->htotal * HV_FACTOR * 1000 / hperiod;
-	drm_mode->clock -= drm_mode->clock % CVT_CLOCK_STEP;
+	tmp = drm_mode->htotal; /* perform intermediate calcs in u64 */
+	tmp *= HV_FACTOR * 1000;
+	do_div(tmp, hperiod);
+	tmp -= drm_mode->clock % CVT_CLOCK_STEP;
+	drm_mode->clock = tmp;
 	/* 18/16. Find actual vertical frame frequency */
 	/* ignore - just set the mode flag for interlaced */
 	if (interlaced) {