id &= V4L2_CTRL_ID_MASK;
                id++;
                for (i = 0; i < gspca_dev->sd_desc->nctrls; i++) {
-                       if (id < gspca_dev->sd_desc->ctrls[i].qctrl.id)
+                       if (gspca_dev->sd_desc->ctrls[i].qctrl.id < id)
                                continue;
                        if (ix < 0) {
                                ix = i;
             i++, ctrls++) {
                if (ctrl->id != ctrls->qctrl.id)
                        continue;
+               if (gspca_dev->ctrl_dis & (1 << i))
+                       return -EINVAL;
                if (ctrl->value < ctrls->qctrl.minimum
                    || ctrl->value > ctrls->qctrl.maximum)
                        return -ERANGE;
             i++, ctrls++) {
                if (ctrl->id != ctrls->qctrl.id)
                        continue;
+               if (gspca_dev->ctrl_dis & (1 << i))
+                       return -EINVAL;
                if (mutex_lock_interruptible(&gspca_dev->usb_lock))
                        return -ERESTARTSYS;
                ret = ctrls->get(gspca_dev, &ctrl->value);