cstate = &pstate->base;
        }
 
-       ret = nouveau_therm_cstate(ptherm, pstate->fanspeed, +1);
-       if (ret && ret != -ENODEV) {
-               nv_error(clk, "failed to raise fan speed: %d\n", ret);
-               return ret;
+       if (ptherm) {
+               ret = nouveau_therm_cstate(ptherm, pstate->fanspeed, +1);
+               if (ret && ret != -ENODEV) {
+                       nv_error(clk, "failed to raise fan speed: %d\n", ret);
+                       return ret;
+               }
        }
 
-       ret = volt->set_id(volt, cstate->voltage, +1);
-       if (ret && ret != -ENODEV) {
-               nv_error(clk, "failed to raise voltage: %d\n", ret);
-               return ret;
+       if (volt) {
+               ret = volt->set_id(volt, cstate->voltage, +1);
+               if (ret && ret != -ENODEV) {
+                       nv_error(clk, "failed to raise voltage: %d\n", ret);
+                       return ret;
+               }
        }
 
        ret = clk->calc(clk, cstate);
                clk->tidy(clk);
        }
 
-       ret = volt->set_id(volt, cstate->voltage, -1);
-       if (ret && ret != -ENODEV)
-               nv_error(clk, "failed to lower voltage: %d\n", ret);
+       if (volt) {
+               ret = volt->set_id(volt, cstate->voltage, -1);
+               if (ret && ret != -ENODEV)
+                       nv_error(clk, "failed to lower voltage: %d\n", ret);
+       }
 
-       ret = nouveau_therm_cstate(ptherm, pstate->fanspeed, -1);
-       if (ret && ret != -ENODEV)
-               nv_error(clk, "failed to lower fan speed: %d\n", ret);
+       if (ptherm) {
+               ret = nouveau_therm_cstate(ptherm, pstate->fanspeed, -1);
+               if (ret && ret != -ENODEV)
+                       nv_error(clk, "failed to lower fan speed: %d\n", ret);
+       }
 
        return 0;
 }