c++hidreadfilewiimote

Readfile on HID sometimes gives wrong values

I have a connection for a WiiMote

handle = CreateFile(didetail->DevicePath, GENERIC_READ|GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
if(handle != INVALID_HANDLE_VALUE) {
    opened = true;
    readReportEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    memset(&readOverlapped, 0, sizeof(readOverlapped));
    readOverlapped.hEvent     = readReportEvent;
    readOverlapped.Offset     = 0;
    readOverlapped.OffsetHigh = 0;

    writeReportEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    memset(&writeOverlapped, 0, sizeof(writeOverlapped));
    writeOverlapped.hEvent    = readReportEvent;
    writeOverlapped.Offset    = 0;
    writeOverlapped.OffsetHigh = 0;
}

I have a thread which always read this handle for new messages:

while(opened && readThreadNextStatus){
    memset (readBuff, 0, 22);
    BYTE* ptrbuff = new BYTE[22];
    int readfile = ReadFile(handle, readBuff, reportLength, NULL, &readOverlapped);
    if(readfile == 0 && GetLastError() == ERROR_IO_PENDING){
        DWORD waitError;
        do 
        {
            waitError = WaitForSingleObject(readReportEvent, timeout);
        } while (waitError == WAIT_TIMEOUT && opened && readThreadNextStatus);

        if(opened && readThreadNextStatus){
            DWORD read = 0;
            if(waitError == WAIT_OBJECT_0){
                GetOverlappedResult(handle, &readOverlapped, &read, TRUE);
            }
            ResetEvent(readReportEvent);
            memcpy(ptrbuff, readBuff, 22);

        cout << "Read:  ";
        coutHex(ptrbuff);
        }
    }
}

My write function:

if(opened){
    if(!WriteFile(handle, buff, reportLength, NULL, &writeOverlapped)){
        if(GetLastError() != ERROR_IO_PENDING){
            close();
        }
    }
    WaitForSingleObject(writeReportEvent, timeout);
    DWORD write = 0;
    GetOverlappedResult(handle, &writeOverlapped, &write, TRUE);
    ResetEvent(writeReportEvent);
}
cout << "Write: ";
coutHex(buff);

Console output:

Connection established
Write: 15- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Read:   0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Read:   0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Write: 15- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Read:   0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Write: 15- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Read:   0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Read:  20- 0- 0-10- 0- 0-49-ff-ff-ff-ff-ff-ff-ff-ff-ff-ff-ff-ff-ff-ff-ff-
Write: 15- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Read:   0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-
Write: 15- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0
Read:   0- 0-
0- 0-
- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0- 0-

coutHex always prints the received data in hex format. Sometimes I get the right data, but sometimes the array is loaded only with 00 00 00 00 00 00 00 00 00 ... 00 00

I experienced that, when I make a write, I always get back a report, which contains just 00's and this appears before my write function make the write on the console output.

I was desperate, so I tried out this:

do 
            {
                waitError = WaitForSingleObject(readReportEvent, timeout);
                Sleep(500);
            } while (waitError == WAIT_TIMEOUT && opened && readThreadNextStatus);

I don't know why, but now it works(not fine, because it has 500ms delay).

What do you think? Maybe ReadFile and WriteFile don't work concurrently?

What causes this? Did I miss something?

Solution

  • There are some additional problems: