diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index c1fe9e0e46d1222f7bbba5190e804459dc5d90da..b489d9481a695da280ed5e4cf7780223f8af91a2 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1451,6 +1451,21 @@ static int __comedi_get_user_cmd(struct comedi_device *dev,
 		return -EINVAL;
 	}
 
+	/*
+	 * Set the CMDF_WRITE flag to the correct state if the subdevice
+	 * supports only "read" commands or only "write" commands.
+	 */
+	switch (s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) {
+	case SDF_CMD_READ:
+		cmd->flags &= ~CMDF_WRITE;
+		break;
+	case SDF_CMD_WRITE:
+		cmd->flags |= CMDF_WRITE;
+		break;
+	default:
+		break;
+	}
+
 	return 0;
 }