libusb_submit_transfer提交成功后没有触发回调函数

[mfqdgy]

大家好，libusb-1.0.18，主函数里重要函数部分：
。。。。。。
ctl_buf = (unsigned char*) malloc(LIBUSB_CONTROL_SETUP_SIZE );
if (!ctl_buf){
printf("Control buffer Malloc ERR\n");
return -ENOMEM;
}

libusb_fill_control_setup(ctl_buf, LIBUSB_RECIPIENT_DEVICE | LIBUSB_REQUEST_TYPE_STANDARD | LIBUSB_ENDPOINT_IN, LIBUSB_REQUEST_GET_DESCRIPTOR,
(1 << 8) | 0, 0, 0);

main_transfer = libusb_alloc_transfer(0);
if (!main_transfer) {
printf("main transfer is NULL\n");
return -ENOMEM;
}

libusb_fill_control_transfer(main_transfer, handle, ctl_buf, callback_fn, NULL, 0);
main_transfer->flags = LIBUSB_TRANSFER_SHORT_NOT_OK | LIBUSB_TRANSFER_FREE_BUFFER | LIBUSB_TRANSFER_FREE_TRANSFER;
printf("Control_Proc submit transfer\n");
ret = libusb_submit_transfer(main_transfer);
printf("Control_Proc submit transfer OVER! return %d length %d actual len %d status %d\n", ret, main_transfer->length, main_transfer->actual_length, main_transfer->status);
。。。。。。
回调函数：
static void callback_fn(struct libusb_transfer *transfer)
{
if (transfer->status != LIBUSB_TRANSFER_COMPLETED) {
printf("callback transfer not completed!\n");
return ;
}

printf("callback status=%d length=%d actual_length=%d\n", transfer->status,
transfer->length, transfer->actual_length);
}

问题： libusb_submit_transfer虽返回0，但并没有触发回调函数，不知道为什么？望大侠指点！

[mfqdgy]

没人回答。。。

[jane_ybf]

请问这个问题你解决了吗？我也碰到了同样的情况

[sky79]

同问，我的是libusb_interrupt_transfer 不能下发数据到设备

[bwlrktjv44240]

我遇到了同样的问题 设备可以正常打开，并且ep也检测出来了 然后用了libusb_bulk_transfer去读写usb，然后没反应……

[m0_37776124]

需要再起个线程，在新线程里循环调用libusb_handle_events或libusb_handle_events_timeout