1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 173b7d335834..f64ac86deb84 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -165,6 +165,7 @@ struct drm_display_mode *drm_cvt_mode(struct drm_device *dev, int hdisplay,
         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 @@ struct drm_display_mode *drm_cvt_mode(struct drm_device *dev, int hdisplay,
                 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) {