I'm thinking of coding something up that will change a laptop's refresh rate based on whether or not the device is plugged in.
From my research, these are two links I came across. One is 20 years old and the other is from Microsoft, but I don't see any mentions of refresh rate specifically.
https://www.codeproject.com/Articles/558/Changing-your-monitor-s-refresh-rate
https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-changedisplaysettingsa?redirectedfrom=MSDN
Does anyone have any insight into how to do this? I'm not too particular about what language would have to be used for it, so let me know whatever would be most viable. Of course I'd also have to be able to check a change in state for plugged in/unplugged, but I haven't gotten to that point yet.
I'm mostly targeting Windows 10 since that's what my device is on.
You can use EnumDisplaySettings to enumerate the information of the current display device, and then set the display by ChangeDisplaySettingsA.
If you want to modify the refresh rate, you only need to modify the dmDisplayFrequency parameter of DEVMODEA.
Here is the sample:
#include <Windows.h>
#include <iostream>
using namespace std;
int main(int argc, const char* argv[])
{
DEVMODE dm;
ZeroMemory(&dm, sizeof(dm));
dm.dmSize = sizeof(dm);
if (0 != EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm))
{
cout << "DisplayFrequency before setting = " << dm.dmDisplayFrequency << endl;
dm.dmDisplayFrequency = 60; //set the DisplayFrequency
LONG ret = ChangeDisplaySettingsEx(NULL, &dm, NULL, 0, NULL);
std::cout << "ChangeDisplaySettingsEx returned " << ret << '\n';
if (0 != EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm))
{
cout << "DisplayFrequency after setting = " << dm.dmDisplayFrequency << endl;
}
switch (ret)
{
case DISP_CHANGE_SUCCESSFUL:
std::cout << "display successfully changed\n";
break;
case DISP_CHANGE_BADDUALVIEW:
std::cout << "The settings change was unsuccessful because the system is DualView capable\n";
break;
case DISP_CHANGE_BADFLAGS:
std::cout << "An invalid set of flags was passed in.\n";
break;
case DISP_CHANGE_BADMODE:
std::cout << "The graphics mode is not supported.\n";
break;
case DISP_CHANGE_BADPARAM:
std::cout << "An invalid parameter was passed in. This can include an invalid flag or combination of flags.\n";
break;
case DISP_CHANGE_FAILED:
std::cout << "The display driver failed the specified graphics mode.\n";
break;
case DISP_CHANGE_NOTUPDATED:
std::cout << "Unable to write settings to the registry.\n";
break;
case DISP_CHANGE_RESTART:
std::cout << "The computer must be restarted for the graphics mode to work.\n";
break;
}
}
system("pause");
}
This example is not always successful. Whether you can modify the refresh rate depends on whether your monitor supports it. This is the output of successful setup:
Related
I have a code that I found on the internet that uses the function GetRawInputDeviceInfo, but it doesn't get the name of the device right. sometimes it doesn't get a name at all. I've searched for an answer and found out that people had this problem on windows XP and windows 7 to. I am using windows 10 so that doesn't really help me.
C++ - WinAPI get list of all connected USB devices (do i need to post the code itself? im new to stack overflow)
At the end of the day what I am trying to do is get the names of all the devices connected to my PC and print them out, but this function doesnt return the name of the mouse either, so if anyone has a suggestion on how to fix it or a better method to get the names Id'e love to hear you'r ideas. thanks in advance, -shon :)
EDIT2! the full code:
#include <windows.h>
#include <iostream>
#include <vector>
#include <string>
#include <set>
// Namespace
using namespace std;
// Main
int main()
{
// Program
cout << "USB Device Lister." << endl;
// Get Number Of Devices
UINT nDevices = 0;
GetRawInputDeviceList(NULL, &nDevices, sizeof(RAWINPUTDEVICELIST));
// Got Any?
if (nDevices < 1)
{
// Exit
cout << "ERR: 0 Devices?";
cin.get();
return 0;
}
// Allocate Memory For Device List
PRAWINPUTDEVICELIST pRawInputDeviceList;
pRawInputDeviceList = new RAWINPUTDEVICELIST[sizeof(RAWINPUTDEVICELIST) * nDevices];
// Got Memory?
if (pRawInputDeviceList == NULL)
{
// Error
cout << "ERR: Could not allocate memory for Device List.";
cin.get();
return 0;
}
// Fill Device List Buffer
int nResult;
nResult = GetRawInputDeviceList(pRawInputDeviceList, &nDevices, sizeof(RAWINPUTDEVICELIST));
// Got Device List?
if (nResult < 0)
{
// Clean Up
delete[] pRawInputDeviceList;
// Error
cout << "ERR: Could not get device list.";
cin.get();
return 0;
}
std::set<std::string> DeviceList;
// Loop Through Device List
for (UINT i = 0; i < nDevices; i++)
{
// Get Character Count For Device Name
UINT nBufferSize = 0;
nResult = GetRawInputDeviceInfo(pRawInputDeviceList[i].hDevice, // Device
RIDI_DEVICENAME, // Get Device Name
NULL, // NO Buff, Want Count!
&nBufferSize); // Char Count Here!
// Got Device Name?
if (nResult < 0)
{
// Error
cout << "ERR: Unable to get Device Name character count.. Moving to next device." << endl << endl;
// Next
continue;
}
// Allocate Memory For Device Name
WCHAR* wcDeviceName = new WCHAR[nBufferSize + 1];
// Got Memory
if (wcDeviceName == NULL)
{
// Error
cout << "ERR: Unable to allocate memory for Device Name.. Moving to next device." << endl << endl;
// Next
continue;
}
// Get Name
nResult = GetRawInputDeviceInfo(pRawInputDeviceList[i].hDevice, // Device
RIDI_DEVICENAME, // Get Device Name
wcDeviceName, // Get Name!
&nBufferSize); // Char Count
// Got Device Name?
if (nResult < 0)
{
// Error
cout << "ERR: Unable to get Device Name.. Moving to next device." << endl << endl;
// Clean Up
delete[] wcDeviceName;
// Next
continue;
}
// Set Device Info & Buffer Size
RID_DEVICE_INFO rdiDeviceInfo;
rdiDeviceInfo.cbSize = sizeof(RID_DEVICE_INFO);
nBufferSize = rdiDeviceInfo.cbSize;
// Get Device Info
nResult = GetRawInputDeviceInfo(pRawInputDeviceList[i].hDevice,
RIDI_DEVICEINFO,
&rdiDeviceInfo,
&nBufferSize);
// Got All Buffer?
if (nResult < 0)
{
// Error
cout << "ERR: Unable to read Device Info.. Moving to next device." << endl << endl;
// Next
continue;
}
// Mouse
if (rdiDeviceInfo.dwType == RIM_TYPEMOUSE)
{
// Current Device
int id = rdiDeviceInfo.mouse.dwId; //device id
string s = "ID: " + std::to_string(id) + ", Type : MOUSE"; //device type is mouse
DeviceList.insert(s);
}
// Keyboard
else if (rdiDeviceInfo.dwType == RIM_TYPEKEYBOARD)
{
// Current Device
cout << endl << "Displaying device " << i + 1 << " information. (KEYBOARD)" << endl;
wcout << L"Name " << wcDeviceName << endl; //*Problem is here!* //
cout << "Keyboard mode: " << rdiDeviceInfo.keyboard.dwKeyboardMode << endl;
cout << "Number of function keys: " << rdiDeviceInfo.keyboard.dwNumberOfFunctionKeys << endl;
cout << "Number of indicators: " << rdiDeviceInfo.keyboard.dwNumberOfIndicators << endl;
cout << "Number of keys total: " << rdiDeviceInfo.keyboard.dwNumberOfKeysTotal << endl;
cout << "Type of the keyboard: " << rdiDeviceInfo.keyboard.dwType << endl;
cout << "Subtype of the keyboard: " << rdiDeviceInfo.keyboard.dwSubType << endl;
}
// Some HID
else // (rdi.dwType == RIM_TYPEHID)
{
// Current Device
cout << endl << "Displaying device " << i + 1 << " information. (HID)" << endl;
wcout << L"Device Name: " << wcDeviceName << endl;
cout << "Vendor Id:" << rdiDeviceInfo.hid.dwVendorId << endl;
cout << "Product Id:" << rdiDeviceInfo.hid.dwProductId << endl;
cout << "Version No:" << rdiDeviceInfo.hid.dwVersionNumber << endl;
cout << "Usage for the device: " << rdiDeviceInfo.hid.usUsage << endl;
cout << "Usage Page for the device: " << rdiDeviceInfo.hid.usUsagePage << endl;
}
// Delete Name Memory!
delete[] wcDeviceName;
}
// Clean Up - Free Memory
delete[] pRawInputDeviceList;
for (std::set<string>::iterator i = DeviceList.begin(); i != DeviceList.end(); ++i)
std::cout << *i << '\n';
// Exit
cout << endl << "Finnished.";
cin.get();
return 0;
}
In Windows there are two flavors of API calls: Unicode and ANSI. The former takes and returns UTF-16 encoded Unicode strings; the latter takes and returns 8-bit encoded strings (the exact encoding depends on the OS localization).
You choose which flavor you want to use by #defining (or not #defining) the macro UNICODE. Depending on that the function changes name, with an W or A suffix.
#ifdef UNICODE
#define GetRawInputDeviceInfo GetRawInputDeviceInfoW
#else
#define GetRawInputDeviceInfo GetRawInputDeviceInfoA
#endif
All the structures that may contain text data are also duplicated with the W or A suffixes.
Now your problem: you are not defining UNICODE so you are actually calling GetRawInputDeviceInfoA(), the ANSI flavor, that expects a char*, but you are passing a WCHAR*, that is a UNICODE string!
The solution is easy:
char* wcDeviceName = new char[nBufferSize + 1];
It is unfortunate that this function GetRawInputDeviceInfo() has its arguments overloaded, so it is declared as taking a void*, so the compiler cannot catch the error. If you were calling a simpler function, say SetWindowText() then you would have got a compiler error because of incompatible pointer type.
If you really want the full UNICODE name of the device, you may prefer keep the WCHAR string and then call the UNICODE function specifically:
WCHAR* wcDeviceName = new WCHAR[nBufferSize + 1];
...
GetRawInputDeviceInfoW(..., RIDI_DEVICENAME, wcDeviceName, ...);
I am trying to develop a program that goes and finds 2 connected unformatted physical drives and read bytes. The program currently runs in the administrator mode since that's the only way I guess the program can see unformatted hard drives. I am using visual studio 2015 and it runs in windows 7 machine.
The problem is that it can only read multiples of 512 (512 is the sector size). Currently the unformatted hard drives are located in disk 2 and 3 slots (they are both SSDs). It first reads 512 bytes (works without an issue) and doesn't do any more reads if it's a formatted hard drive. If it's an unformatted hard drive it goes ahead and read more bytes. If it's hard drive A it then reads the next 1024 bytes and it works (read_amount = 1024). If it's hard drive B it then reads the next 1025 bytes and it doesn't work (read_amount = 0). I am not sure why it can't read a multiple of a 512/sector sizes. My understanding is that when you call "CreateFile()" function with dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL, I should be able to read sizes that are not multiples of sector sizes (if you use FILE_FLAG_NO_BUFFERING then you can only read multiples of 512 and I am NOT using that flag). See my code below.
// Hard_Drive_Read.cpp : Defines the entry point for the console application.
// This program assumes you have EXACTLY TWO unformatted hard drives connected to your computer.
#include <Windows.h>
#include <io.h>
#include <fcntl.h>
#include <fstream>
#include <iostream>
#include <iomanip>
using namespace std;
int main(int argc, char *argv[])
{
if (argc != 3)
{
cout << "Need to enter 2 arguments" << endl;
exit(0);
}
int frames_to_process = atoi(argv[2]);
if (frames_to_process < 1)
{
cout << "invalid argument 2" << endl;
exit(0);
}
//HANDLE hDisk_A;
//HANDLE hDisk_B;
LPCTSTR dsksrc = L"\\\\.\\PhysicalDrive";
wchar_t dsk[512] = L"";
bool channel_A_found = false;
bool channel_B_found = false;
char frame_header_A[1024];
char frame_header_B[1025];
HANDLE hDisk;
char buff_read[512];
DWORD read_amount = 0;
for (int i = 0; i < 4; i++)
{
swprintf(dsk, 511, L"%s%d", dsksrc, i);
hDisk = CreateFile(dsk, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (hDisk == INVALID_HANDLE_VALUE)
{
printf("%s%d%s", "couldn't open the drive ", i, "\n");
CloseHandle(hDisk);
}
else
{
printf("%s%d%s", "successfully open the drive ", i, "\n");
BOOL read_success_1 = ReadFile(hDisk, buff_read, 512, &read_amount, NULL);
cout << "read amount 1 - " << read_amount << endl;
if ((read_success_1 == TRUE) && (read_amount == 512))
{
if ((buff_read[510] == (char)0x55) && (buff_read[511] == (char)0xAA)) // test for a formatted drive; is there other identifiers?
{
cout << i << " is a formatted drive" << endl;
}
else
{
cout << "Not a formatted drive, trying to find sync " << endl;
ofstream writeBinary_Test;
if (i == 2)
{
writeBinary_Test.open("file_A_test.bin", ofstream::out | ofstream::binary);
ReadFile(hDisk, frame_header_A, 1024, &read_amount, NULL);
cout << "read amount " << read_amount << endl;
writeBinary_Test.write(frame_header_A, 1024);
writeBinary_Test.close();
}
else if(i == 3)
{
writeBinary_Test.open("file_B_test.bin", ofstream::out | ofstream::binary);
ReadFile(hDisk, frame_header_B, 1025, &read_amount, NULL);
cout << "read amount " << read_amount << endl;
writeBinary_Test.write(frame_header_B, 1025);
writeBinary_Test.close();
}
LARGE_INTEGER distanceToMove;
SetFilePointerEx(hDisk, distanceToMove, NULL, FILE_BEGIN);
}
}
else
{
}
}
if (channel_A_found && channel_B_found)
{
cout << "both drives found" << endl;
break;
}
}
if ((channel_A_found == false) || (channel_B_found == false))
{
cout << "Couldn't Find Hard Drive A or Drive B or Both" << endl;
cout << "Exiting the program" << endl;
exit(0);
}
CloseHandle(hDisk);
return 0;
}
Eventually, I want to use SetFilePointerEx() to move around the hard drive and I the program has to work with and data size (not multiples of 512). Therefore, it's imperative I can read sizes that's not multiples of 512. Any ideas of how to fix this program? Am I using my flags properly?
Any help is much appreciated!
The documentation for CreateFile says:
Volume handles can be opened as noncached at the discretion of the particular file system, even when the noncached option is not specified in CreateFile. You should assume that all Microsoft file systems open volume handles as noncached. The restrictions on noncached I/O for files also apply to volumes.
Although it doesn't spell it out explicitly, this applies to drives as well as to volumes.
In practice, this isn't a problem. It is straightforward to write a helper function that returns an arbitrary amount of data from an arbitrary offset, while performing only aligned reads.
It's imperative I can read sizes that's not multiples of 512.
That is not possible. For direct access of a disk, you can only read and write multiples of the sector size. Furthermore, you must align your read and write operations. That is the file pointer must be at a multiple of the sector size.
If you want to present an interface that allows arbitrary seeking, reading and writing, then you will need to implement your own buffering on top of the aligned raw disk access.
I am using Dlib 19.2 with VS2015 .I was executing the below program as mentioned in this link 'http://dlib.net/webcam_face_pose_ex.cpp'
I want to save the video with all landmarks on each frame.How can I do this?
I am running the below code.
int main(){
try{
cv::VideoCapture cap("out.avi");
int count =cap.get(CV_CAP_PROP_FRAME_COUNT);
if (!cap.isOpened())
{
cout << "Unable to connect to camera" << endl;
return 1;
}
image_window win;
// Load face detection and pose estimation models.
frontal_face_detector detector = get_frontal_face_detector();
shape_predictor pose_model;
deserialize("shape_predictor_68_face_landmarks.dat") >> pose_model;
// Grab and process frames until the main window is closed by the user.
while (!win.is_closed())
{
// Grab a frame
cv::Mat temp;
cap >> temp;
// Turn OpenCV's Mat into something dlib can deal with. Note that this just
// wraps the Mat object, it doesn't copy anything. So cimg is only valid as
// long as temp is valid. Also don't do anything to temp that would cause it
// to reallocate the memory which stores the image as that will make cimg
// contain dangling pointers. This basically means you shouldn't modify temp
// while using cimg.
cv_image<bgr_pixel> cimg(temp);
// Detect faces
std::vector<rectangle> faces = detector(cimg);
// Find the pose of each face.
std::vector<full_object_detection> shapes;
for (unsigned long i = 0; i < faces.size(); ++i)
shapes.push_back(pose_model(cimg, faces[i]));
// Display it all on the screen
win.clear_overlay();
win.set_image(cimg);
win.add_overlay(render_face_detections(shapes));
waitKey(20);
}
}
catch (serialization_error& e)
{
cout << "You need dlib's default face landmarking model file to run this example." << endl;
cout << "You can get it from the following URL: " << endl;
cout << " http://dlib.net/files/shape_predictor_68_face_landmarks.dat.bz2" << endl;
cout << endl << e.what() << endl;
}
catch (exception& e)
{
cout << e.what() << endl;
}
getch();
}
So please guide me on this.
I am creating a large pintool and I have two questions:
The tool (abridged below to the relevant part only) sometimes cannot identify the image/routine for particular executed instructions. Does anybody know when/why can that happen?
The tool (when instrumenting a Barnes-Hut benchmark) always terminates with an out-of-memory (OOM) error after running for a while (although the benchmark, when run standalone, completes successfully). Which tools to use to debug/trace the OOM error of Pin-instrumented applications?
int main(int argc, char *argv[])
{
PIN_InitSymbols();
if( PIN_Init(argc, argv) )
{
return 0;
}
INS_AddInstrumentFunction(Instruction, 0);
PIN_StartProgram();
return 0;
}
VOID Instruction(INS ins, VOID *v)
{
INS_InsertPredicatedCall( ins,
IPOINT_BEFORE,
(AFUNPTR) handle_ins_execution,
IARG_INST_PTR,
.....);
}
VOID handle_ins_execution (ADDRINT addr, ...)
{
PIN_LockClient();
IMG img = IMG_FindByAddress(addr);
RTN rtn = RTN_FindByAddress(addr);
PIN_UnlockClient();
if( IMG_Valid(img) ) {
std::cerr << "From Image : " << IMG_Name( img ) << std::endl;
} else {
std::cerr << "From Image : " << "(UKNOWN)" << std::endl;
}
if( RTN_Valid(rtn) ) {
std::cerr << "From Routine : " << RTN_Name(rtn) << std::endl;
} else {
std::cerr << "From Routine : " << "(UKNOWN)" << std::endl;
}
}
I recently asked this on the PinHeads forum, and I'm awaiting a response. What I have read in the documentation is that the IMG_FindByAddress function operates by looking "for each image, check if the address is within the mapped memory region of one of its segments." It may be possible that instructions are executed that are not within the valid ranges.
The best way to know what image it is in for cases like this is to look at the context. My pintool (based on DebugTrace) continues to run even without knowing what image it is in. You can look at the log entries before and after this occurs. I see this all the time in dydl on OSX.
Bugfix update:
As of Jun, 2013 FTDI did acknowledge to me that the bug was real. They have since released a new version of their driver (2.8.30.0, dated 2013-July-12) that fixes the problem. The driver made it through WHQL around the first of August, 2013 and is available via Windows Update at this time.
I've re-tested running the same test code and am not able to reproduce the problem with the new driver, so at the moment the fix seems to be 'upgrade the driver'.
The original question:
I've got an 8 port USB-serial device (from VsCOM) that is based on the FTDI FT2232D chip. When I transmit at certain settings from one of the ports, AND I use the hardware handshaking to stop and start the data flow from the other end, I get two symptoms:
1) The output data sometimes becomes garbage. There will be NUL characters, and pretty much any random thing you can think of.
2) The WriteFile call will sometimes return a number of bytes GREATER than the number I asked it to write. That's not a typo. I ask for 30 bytes to be transmitted and the number of bytes sent comes back 8192 (and yes, I do clear the number sent to 0 before I make the call).
Relevant facts:
Using FTDI drivers 2.8.24.0, which is the latest as of today.
Serial port settings are 19200, 7 data bits, odd parity, 1 stop bit.
I get this same behavior with another FTDI based serial device, this time a single port one.
I get the same behavior with another 8 port device of the same type.
I do NOT get this behavior when transmitting on the built-in serial ports (COM1).
I have a very simple 'Writer' program that just transmits continuously and a very simple 'Toggler' program that toggles RTS once per second. Together these seem to trigger the issue within 60 seconds.
I have put an issue into the manufacturer of the device, but they've not yet had much time to respond.
Compiler is mingw32, the one included with the Qt installer for Qt 4.8.1 (gcc 4.4.0)
I'd like to know first off, if there's anything that anyone can think of that I could possibly do to trigger this behavior. I can't conceive of anything, but there's always things I don't know.
Secondly, I've attached the Writer and Toggler test programs. If anyone can spot some issue that might trigger the program, I'd love to hear about it. I have a lot of trouble thinking that there is a driver bug (especially from something as mature as the FTDI chip), but the circumstances force me to think that there's at least SOME driver involvement. At the least, no matter what I do to it, it shouldn't be returning a number of bytes written greater than what I asked it to write.
Writer program:
#include <iostream>
#include <string>
using std::cerr;
using std::endl;
#include <stdio.h>
#include <windows.h>
int main(int argc, char **argv)
{
cerr << "COM Writer, ctrl-c to end" << endl;
if (argc != 2) {
cerr << "Please specify a COM port for parameter 2";
return 1;
}
char fixedbuf[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
std::string portName = "\\\\.\\";
portName += argv[1];
cerr << "Transmitting on port " << portName << endl;
HANDLE ph = CreateFileA( portName.c_str(),
GENERIC_READ | GENERIC_WRITE,
0, // must be opened with exclusive-access
NULL, // default security attributes
OPEN_EXISTING, // must use OPEN_EXISTING
0, // overlapped I/O
NULL ); // hTemplate must be NULL for comm devices
if (ph == INVALID_HANDLE_VALUE) {
cerr << "CreateFile " << portName << " failed, error " << GetLastError() << endl;
return 1;
}
COMMCONFIG ccfg;
DWORD ccfgSize = sizeof(COMMCONFIG);
ccfg.dwSize = ccfgSize;
GetCommConfig(ph, &ccfg, &ccfgSize);
GetCommState(ph, &(ccfg.dcb));
ccfg.dcb.fBinary=TRUE;
ccfg.dcb.fInX=FALSE;
ccfg.dcb.fOutX=FALSE;
ccfg.dcb.fAbortOnError=FALSE;
ccfg.dcb.fNull=FALSE;
// Camino is 19200 7-O-1
ccfg.dcb.BaudRate = 19200;
ccfg.dcb.Parity = ODDPARITY;
ccfg.dcb.fParity = TRUE;
ccfg.dcb.ByteSize = 7;
ccfg.dcb.StopBits = ONESTOPBIT;
// HW flow control
ccfg.dcb.fOutxCtsFlow=TRUE;
ccfg.dcb.fRtsControl=RTS_CONTROL_HANDSHAKE;
ccfg.dcb.fInX=FALSE;
ccfg.dcb.fOutX=FALSE;
COMMTIMEOUTS ctimeout;
DWORD tout = 10;// 10 ms
ctimeout.ReadIntervalTimeout = tout;
ctimeout.ReadTotalTimeoutConstant = tout;
ctimeout.ReadTotalTimeoutMultiplier = 0;
ctimeout.WriteTotalTimeoutMultiplier = tout;
ctimeout.WriteTotalTimeoutConstant = 0;
SetCommConfig(ph, &ccfg, sizeof(COMMCONFIG));
SetCommTimeouts(ph, &ctimeout);
DWORD nwrite = 1;
for(;;) {
nwrite++;
if (nwrite > 30) nwrite = 1;
DWORD nwritten = 0;
if (!WriteFile(ph, fixedbuf, nwrite, &nwritten, NULL)) {
cerr << "f" << endl;
}
if ((nwritten != 0) && (nwritten != nwrite)) {
cerr << "nwrite: " << nwrite << " written: " << nwritten << endl;
}
}
return 0;
}
Toggler program:
#include <iostream>
#include <string>
using std::cerr;
using std::endl;
#include <stdio.h>
#include <windows.h>
int main(int argc, char **argv)
{
cerr << "COM Toggler, ctrl-c to end" << endl;
cerr << "Flips the RTS line every second." << endl;
if (argc != 2) {
cerr << "Please specify a COM port for parameter 2";
return 1;
}
std::string portName = "\\\\.\\";
portName += argv[1];
cerr << "Toggling RTS on port " << portName << endl;
HANDLE ph = CreateFileA( portName.c_str(),
GENERIC_READ | GENERIC_WRITE,
0, // must be opened with exclusive-access
NULL, // default security attributes
OPEN_EXISTING, // must use OPEN_EXISTING
0, // overlapped I/O
NULL ); // hTemplate must be NULL for comm devices
if (ph == INVALID_HANDLE_VALUE) {
cerr << "CreateFile " << portName << " failed, error " << GetLastError() << endl;
return 1;
}
COMMCONFIG ccfg;
DWORD ccfgSize = sizeof(COMMCONFIG);
ccfg.dwSize = ccfgSize;
GetCommConfig(ph, &ccfg, &ccfgSize);
GetCommState(ph, &(ccfg.dcb));
ccfg.dcb.fBinary=TRUE;
ccfg.dcb.fInX=FALSE;
ccfg.dcb.fOutX=FALSE;
ccfg.dcb.fAbortOnError=FALSE;
ccfg.dcb.fNull=FALSE;
// Camino is 19200 7-O-1
ccfg.dcb.BaudRate = 19200;
ccfg.dcb.Parity = ODDPARITY;
ccfg.dcb.fParity = TRUE;
ccfg.dcb.ByteSize = 7;
ccfg.dcb.StopBits = ONESTOPBIT;
// no flow control (so we can do manually)
ccfg.dcb.fOutxCtsFlow=FALSE;
ccfg.dcb.fRtsControl=RTS_CONTROL_DISABLE;
ccfg.dcb.fInX=FALSE;
ccfg.dcb.fOutX=FALSE;
COMMTIMEOUTS ctimeout;
DWORD tout = 10;// 10 ms
ctimeout.ReadIntervalTimeout = tout;
ctimeout.ReadTotalTimeoutConstant = tout;
ctimeout.ReadTotalTimeoutMultiplier = 0;
ctimeout.WriteTotalTimeoutMultiplier = tout;
ctimeout.WriteTotalTimeoutConstant = 0;
SetCommConfig(ph, &ccfg, sizeof(COMMCONFIG));
SetCommTimeouts(ph, &ctimeout);
bool rts = true;// true for set
for(;;) {
if (rts)
EscapeCommFunction(ph, SETRTS);
else
EscapeCommFunction(ph, CLRRTS);
rts = !rts;
Sleep(1000);// 1 sec wait.
}
return 0;
}
I don't have a good answer yet from FTDI, but I've got the following suggestions for anyone dealing with this issue:
1) Consider switching to a non-FTDI usb-serial converter. This is what my company did, but certainly this isn't an option for everyone (we're putting the chip in our own product). We're using Silicon Labs chips now, but I think there are one or two other vendors as well.
2) Per Hans Passant in the comments - reconsider the use of RTS/CTS signalling. If the writes don't fail due to blocking, then you shouldn't trigger this bug.
3) Set all writes to infinite timeout. Again, no fail due to blocking, no triggering of the bug. This may not be appropriate for all applications, of course.
Note that if pursuing strategy #3, if Overlapped IO is used for writes, then CancelIo and it's newer cousin CancelIoEx could be used to kill off the writes if necessary. I have NOT tried doing so, but I suspect that such cancels might also result in triggering this bug. If they were only used when closing the port anyway, then it might be you could get away with it, even if they do trigger the bug.
If anyone else is still seeing this -- update your FTDI driver to 2.8.30.0 or later, as this is caused by a driver bug in earlier versions of the FTDI driver.