mater代码需要修改的serial_fops_poll地方mask |= POLLIN;

[supperthomas]

static int serial_fops_poll(struct dfs_file *fd, struct rt_pollreq *req)
{
    int mask = 0;
    int flags = 0;
    rt_device_t device;
    struct rt_serial_device *serial;

    device = (rt_device_t)fd->vnode->data;
    RT_ASSERT(device != RT_NULL);

    serial = (struct rt_serial_device *)device;

    /* only support POLLIN */
    flags = fd->flags & O_ACCMODE;
    if (flags == O_RDONLY || flags == O_RDWR)
    {
        rt_base_t level;
        struct rt_serial_rx_fifo* rx_fifo;

        rt_poll_add(&(device->wait_queue), req);

        rx_fifo = (struct rt_serial_rx_fifo*) serial->serial_rx;

        level = rt_spin_lock_irqsave(&(serial->spinlock));
        if ((rx_fifo->get_index != rx_fifo->put_index) || (rx_fifo->get_index == rx_fifo->put_index && rx_fifo->is_full == RT_TRUE))
            mask |= POLLIN;
        rt_spin_unlock_irqrestore(&(serial->spinlock), level);
    }
    mask|=POLLOUT;
    return mask;
}