我想使用用户空间库在Linux中编写和读取USB HID设备的响应。谷歌搜索了一段时间，我发现libhid将成为问题的解决方案。
因此，当我使用hid_interrupt_write和hid_interrupt_read发送和接收数据时，发生了以下错误：
error submitting URB: No such file or directory
但是当我尝试使用hid_set_output_report和hid_get_input_report来编写和读取设备时，发生了以下错误：
error sending control message: Connection timed out.
和
error submitting URB: No such file or directory
并且，我不确定如何获取Usage_Path。
有人可以帮我解决这个问题吗？有什么建议吗？
以下是执行时的源代码及其结果：
#include <hid.h>
#include <stdio.h>
#include <string.h>
#define EP_HID_IN 0x81
#define EP_HID_OUT 0x02
#define PACKET_INT_LEN 8
char command[8];
char answer[8];
const int PATHLEN = 2;
int const PATH_IN[2] = { 0xffff0001, 0xffff0003 };
int const PATH_OUT[2] = {0xffff0001, 0xffff0005 };
const int SEND_PACKET_LEN = 8;
const int RECV_PACKET_LEN = 8;
bool match_serial_number(struct usb_dev_handle* usbdev, void* custom, unsigned int len)
{
bool ret;
char* buffer = (char*)malloc(len);
usb_get_string_simple(usbdev, usb_device(usbdev)->descriptor.iSerialNumber,
buffer, len);
ret = strncmp(buffer, (char*)custom, len) == 0;
free(buffer);
return ret;
}
int main(void)
{
HIDInterface* hid;
hid_return ret;
int i = 0;
HIDInterfaceMatcher matcher = { 0x03eb, 0x4b4e, NULL, NULL, 0 };
/* see include/debug.h for possible values */
hid_set_debug(HID_DEBUG_ALL);
hid_set_debug_stream(stderr);
/* passed directly to libusb */
hid_set_usb_debug(1);
ret = hid_init();
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_init failed with return code %d\n", ret);
return 1;
}
hid = hid_new_HIDInterface();
if (hid == 0) {
fprintf(stderr, "hid_new_HIDInterface() failed, out of memory?\n");
return 1;
}
ret = hid_force_open(hid, 0, &matcher, 3);
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_force_open failed with return code %d\n", ret);
return 1;
}
ret = hid_write_identification(stdout, hid);
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_write_identification failed with return code %d\n", ret);
return 1;
}
ret = hid_dump_tree(stdout, hid);
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_dump_tree failed with return code %d\n", ret);
return 1;
}
// Set command,
command[0] = 0x03;
command[1] = 0x01;
command[2] = 0x31;
command[3] = 0x31;
command[4] = 0x04;
command[5] = 0x00;
command[6] = 0x00;
command[7] = 0x00;
/*
ret = hid_set_output_report(hid, PATH_IN, PATHLEN, command, SEND_PACKET_LEN);
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_set_output_report failed with return code %d\n", ret);
}
ret = hid_get_input_report(hid, PATH_OUT, PATHLEN, answer, RECV_PACKET_LEN);
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_get_input_report failed with return code %d\n", ret);
}
*/
ret = hid_interrupt_write(hid, EP_HID_OUT, command, PACKET_INT_LEN, 20);
if (ret < 0) {
printf("error in interrupt write\n");
return 1;
}
printf("Reading interrupt\n");
ret = hid_interrupt_read(hid, EP_HID_IN, answer, PACKET_INT_LEN, 4);
if(ret < 0) {
printf("error interrupt read\n");
return 1;
}
printf("Interrupt Transfer Loop Test Result:\n");
for(i = 0;i < PACKET_INT_LEN; i++) {
if(i%8 == 0)
printf("\n");
printf("%02x; ",command[i]);
}
printf("\n");
printf("\n");
for(i = 0;i < PACKET_INT_LEN; i++) {
if(i%8 == 0)
printf("\n");
printf("%02x; ",answer[i]);
}
printf("\n");
printf("\n");
ret = hid_close(hid);
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_close failed with return code %d\n", ret);
return 1;
}
hid_delete_HIDInterface(&hid);
ret = hid_cleanup();
if (ret != HID_RET_SUCCESS) {
fprintf(stderr, "hid_cleanup failed with return code %d\n", ret);
return 1;
}
return 0;
}
结果：
# ./test_libhid
usb_set_debug: Setting debugging level to 1 (on)
NOTICE: hid_init(): libhid 0.2.15+20060325.0.0 is being initialized.
TRACE: hid_init(): initialising USB subsystem...
usb_os_init: Found USB VFS at /dev/bus/usb
...
...
device identification of HIDInterface 002/009[0]:
dev_handle: 0x09a52098
device: 0x09a55068
location: 002/009
manufacturer: ATMEL
product: Firmware Demo
TRACE: hid_reset_parser(): resetting the HID parser for USB device 002/009[0]...
TRACE: hid_dump_tree(): iterating the parse tree for USB device 002/009[0]...
parse tree of HIDInterface 002/009[0]:
path: 0xffff0001.0xffff0002; type: 0x80
path: 0xffff0001.0xffff0003; type: 0x80
path: 0xffff0001.0x00000000; type: 0x80
path: 0xffff0001.0x00000000; type: 0x80
path: 0xffff0001.0x00000000; type: 0x80
path: 0xffff0001.0x00000000; type: 0x80
path: 0xffff0001.0x00000000; type: 0x80
path: 0xffff0001.0x00000000; type: 0x80
path: 0xffff0001.0xffff0004; type: 0x90
path: 0xffff0001.0xffff0005; type: 0x90
path: 0xffff0001.0x00000000; type: 0x90
path: 0xffff0001.0x00000000; type: 0x90
path: 0xffff0001.0x00000000; type: 0x90
path: 0xffff0001.0x00000000; type: 0x90
path: 0xffff0001.0x00000000; type: 0x90
path: 0xffff0001.0x00000000; type: 0x90
path: 0xffff0001.0xffff0006; type: 0xb0
path: 0xffff0001.0xffff0007; type: 0xb0
path: 0xffff0001.0x00000000; type: 0xb0
path: 0xffff0001.0x00000000; type: 0xb0
TRACE: hid_reset_parser(): resetting the HID parser for USB device 002/009[0]...
TRACE: hid_set_output_report(): looking up report ID...
TRACE: hid_prepare_parse_path(): preparing search path of depth 2 for parse tree of USB device 002/009[0]...
TRACE: hid_prepare_parse_path(): search path prepared for parse tree of USB device 002/009[0].
NOTICE: hid_find_object(): found requested item.
TRACE: hid_set_output_report(): sending report ID 0x00 (length: 8) to USB device 002/009[0]...
WARNING: hid_set_output_report(): failed to send report to USB device 002/009[0]:error sending control message: Connection timed out.
hid_set_output_report failed with return code 19
Reading interrupt
TRACE: hid_interrupt_read(): retrieving interrupt report from device 002/009[0] ...
WARNING: hid_interrupt_read(): failed to get interrupt read from device 002/009[0]: error submitting URB: No such file or directory
Interrupt Transfer Loop Test Result:
03; 01; 31; 31; 04; 00; 00; 00;
00; 00; 00; 00; 00; 00; 00; 00;
TRACE: hid_close(): closing USB device 002/009[0]...
TRACE: hid_close(): closing handle of USB device 002/009[0]...
NOTICE: hid_close(): successfully closed USB device 002/009[0].
TRACE: hid_reset_parser(): resetting the HID parser for USB device 002/009[0]...
TRACE: hid_close(): freeing memory allocated for HID parser...
TRACE: hid_close(): resetting HIDInterface...
NOTICE: hid_cleanup(): successfully deinitialised HID library.
答案 0 :(得分：1)
Libhid建立在libusb之上。老实说，libusb是一个更好的库。这使得来回沟通变得非常容易。事实上，如果您感兴趣，我可以向您发送一个读取和写入HID设备的示例程序。
Libhid需要付出更多努力，文档更糟糕。
当然，无论哪种方式，您都必须确保写入正确的设备（通过检查产品和供应商ID），并且如果使用libhid，还要将正确的数据包发送到正确的路径。 （有三种路径：输入，输出和功能）。
我真的建议使用libusb。