diff --git a/drivers/gpu/drm/nouveau/nv50_pm.c b/drivers/gpu/drm/nouveau/nv50_pm.c
index 64bc29c..e703ca1 100644
--- a/drivers/gpu/drm/nouveau/nv50_pm.c
+++ b/drivers/gpu/drm/nouveau/nv50_pm.c
@@ -56,6 +56,11 @@ nv50_pm_clock_get(struct drm_device *dev, u32 id)
 		N = (reg1 & 0x0000ff00) >> 8;
 		M = (reg1 & 0x000000ff);
 
+		if (N == 0 || M == 0) {
+			NV_ERROR(dev, "can't calc clock for id=%d, reg0:0x%x, reg1:0x%x\n", id, reg0, reg1);
+			return -EINVAL;
+		}
+
 		return ((pll.refclk * N / M) >> P);
 	}
 
@@ -63,6 +68,12 @@ nv50_pm_clock_get(struct drm_device *dev, u32 id)
 	P = (reg0 & 0x003f0000) >> 16;
 	N = (reg0 & 0x0000ff00) >> 8;
 	M = (reg0 & 0x000000ff);
+
+	if (N == 0 || M == 0 || P == 0) {
+		NV_ERROR(dev, "can't calc clock for id=%d, reg0:0x%x\n", id, reg0);
+		return -EINVAL;
+	}
+
 	return pll.refclk * N / M / P;
 }