有一款摄像头，需要用到libusb库。 配置信息如下： vid=525，pid=a4a0,bInterfaceClass=ff,bInterfaceSubClass=f0,bmAttributes=2, bInEndpointAddress=82,bOutEndpointAddress=2,bInterfaceNumber=0 在使用libusb_bulk_transfer函数时，返回出错，返回值为-11；
nt rlen;
unsigned char buf[64];
int len = libusb_bulk_transfer(usb_handle, BULK_SEND_EP, buf, len, &rlen, TRANSFER_TIMEOUT);
请问是什么原因引起的？ 不能上传文件：下面是完整的demo
#include "stdio.h"
#include "libusb.h"
#include "usb.h"
#define BULK_RECV_EP 0x82
#define BULK_SEND_EP 0x02
#define INT_RECV_EP 0x81
#define INT_SEND_EP 0x01
#define TRANSFER_TIMEOUT 0
#define PID 0xa4a0
#define VID 0x0525
typedef struct {
unsigned int pid;
unsigned int vid;
unsigned char bInterfaceClass;
unsigned char bInterfaceSubClass;
unsigned char bmAttributes;
unsigned char bInEndpointAddress;
unsigned char bOutEndpointAddress;
unsigned char bInterfaceNumber;
libusb_device *dev;
libusb_device **devs;
} usb_dev;
static libusb_device_handle* usb_handle;
static usb_dev udev;
/*
根据PID与VID检查指定设备是否挂载。
*/
static int get_device_descriptor(struct libusb_device_descriptor *dev_desc, usb_dev* user_device)
{
int rv = -2;
int i = 0;
libusb_device **devs;
libusb_device *dev;
rv = libusb_get_device_list(NULL, &devs);
if (rv < 0)
return rv;
//遍历USB设备
/*
while ((dev = devs[i++]) != NULL) {
rv = libusb_get_device_descriptor(dev, dev_desc);
if(rv == 0) {
}
}
*/
i = 0;
while ((dev = devs[i++]) != NULL) {
rv = libusb_get_device_descriptor(dev,dev_desc);
if(rv < 0) {
//printf("321\n");
return -1;
}
printf("pid=%x,vid=%x\n",dev_desc->idProduct,dev_desc->idVendor);
if(dev_desc->idProduct == user_device->pid && dev_desc->idVendor == user_device->vid)
{
user_device->dev = dev;
user_device->devs = devs;
return 0;
}
}
return -2;
}
int match_with_endpoint(const struct libusb_interface_descriptor * interface,usb_dev *user_device)
{
int i;
int ret=0;
printf("bNumEndpoints:%d\n", interface->bNumEndpoints);
for(i=0; i<interface->bNumEndpoints; i++)
{ printf("interface->endpoint[i].bmAttributes&0x03:%d,user_device->bmAttributes=%d\n", interface->endpoint[i].bmAttributes&0x03,user_device->bmAttributes);
if((interface->endpoint[i].bmAttributes&0x03)==user_device->bmAttributes) //transfer type :bulk ,control, interrupt
{ printf("interface->endpoint[i].bEndpointAddress:%d\n", interface->endpoint[i].bEndpointAddress);
if(interface->endpoint[i].bEndpointAddress&0x80) //out endpoint & in endpoint
{
ret|=1;
user_device->bInEndpointAddress = interface->endpoint[i].bEndpointAddress;//82
}
else
{
ret|=2;
user_device->bOutEndpointAddress = interface->endpoint[i].bEndpointAddress;//02
}
}
}
if(ret==3)
{
return 1;
}
else
{
return 0;
}
}
static int get_device_endpoint(struct libusb_device_descriptor *dev_desc, usb_dev* user_device)
{
int rv = -2;
int i,j,k;
struct libusb_config_descriptor *conf_desc;
unsigned char isFind = 0;
for (i = 0; i < dev_desc->bNumConfigurations; i++)
{
if(user_device->dev != NULL)
rv = libusb_get_config_descriptor(user_device->dev, i, &conf_desc);
if(rv < 0) {
return -1;
}
for (j = 0; j < conf_desc->bNumInterfaces; j++)
{
for (k=0; k < conf_desc->interface[j].num_altsetting; k++)
{
if(conf_desc->interface[j].altsetting[k].bInterfaceClass == user_device->bInterfaceClass)
{
if(match_with_endpoint(&(conf_desc->interface[j].altsetting[k] ), user_device))
{
user_device->bInterfaceNumber = conf_desc->interface[j].altsetting[k].bInterfaceNumber;
libusb_free_config_descriptor(conf_desc);
rv = 0;
return rv;
}
}
}
}
}
return -2; //don't find user device
}
int main()
{
//printf("1111111111\n");
usb_handle = NULL;
struct libusb_device_descriptor udev_desc;
//1. load user data.
udev.pid = PID;
udev.vid = VID;
udev.bInterfaceClass = LIBUSB_CLASS_VENDOR_SPEC;// ff
udev.bInterfaceSubClass = 0xf0;//f0
udev.bmAttributes = LIBUSB_TRANSFER_TYPE_BULK;//c0 00 02
udev.dev = NULL;
// //2. init libusb.
int ret = libusb_init(NULL);
if(ret < 0)
{
return -1;
}
//printf("333333333\n");
//3. search for specified usb device.
ret = get_device_descriptor(&udev_desc, &udev);
if(ret < 0) {
return -2;
}
ret = get_device_endpoint(&udev_desc, &udev);
if(ret < 0) {
return -3;
}
/*4.open device and start communication by usb*/
//open the usb device
usb_handle = libusb_open_device_with_vid_pid(NULL, udev.vid, udev.pid);
if(usb_handle == NULL) {
return -4;
}
ret = libusb_claim_interface(usb_handle, udev.bInterfaceNumber);
if(ret < 0) {
ret = libusb_detach_kernel_driver(usb_handle, udev.bInterfaceNumber);
if(ret < 0) {
return -5;
}
ret = libusb_claim_interface(usb_handle, udev.bInterfaceNumber);
if(ret < 0)
{
return -6;
}
}
printf("vid=%x，pid=%x,bInterfaceClass=%x,bInterfaceSubClass=%x,bmAttributes=%x,bInEndpointAddress=%x,bOutEndpointAddress=%x,bInterfaceNumber=%x\n",
udev.vid,udev.pid,udev.bInterfaceClass,udev.bInterfaceSubClass,udev.bmAttributes,udev.bInEndpointAddress,udev.bOutEndpointAddress,udev.bInterfaceNumber);
//5，通信。
//接收
int rlen;
unsigned char buf[64];
int len = libusb_bulk_transfer(usb_handle, BULK_SEND_EP, buf, len, &rlen, TRANSFER_TIMEOUT);
printf("len:%d，buf=%s\n", len,buf);
//发送
/*
printf("88888888\n");
int wlen;
unsigned char data[64];
len = libusb_bulk_transfer(usb_handle, INT_SEND_EP, data, len, &wlen, TRANSFER_TIMEOUT);
*/
//6，注销
libusb_close(usb_handle);
libusb_release_interface(usb_handle, udev.bInterfaceNumber);
libusb_free_device_list(udev.devs, 1);
libusb_exit(NULL);
usb_handle = NULL;
return 0;
}
