I'm trying to write a custom 'driver' for a keyboard (HID, if it matters), under Windows 7. The final goal is having two keyboards connected to the computer, but mapping all of the keys of one of them to special (custom) functions.
My idea is to use libusb-win32 as the 2nd keyboard's driver, and write a small program to read data from the keyboard and act upon it. I've successfully installed the driver, and the device is recognized from my program, but all transfers timeout, even though I'm pressing keys.
here's my code:
struct usb_bus *busses;
struct usb_device *dev;
char buf[1024];
usb_init();
usb_find_busses();
usb_find_devices();
busses = usb_get_busses();
dev = busses->devices;
cout << dev->descriptor.idVendor << '\n' << dev->descriptor.idProduct << '\n';
usb_dev_handle *h = usb_open(dev);
cout << usb_set_configuration(h, 1) << '\n';
cout << usb_claim_interface(h, 0) << '\n';
cout << usb_interrupt_read(h, 129, buf, 1024, 5000) << '\n';
cout << usb_strerror();
cout << usb_release_interface(h, 0) << '\n';
cout << usb_close(h) << '\n';
and it returns:
1133
49941
0
0
-116
libusb0-dll:err [_usb_reap_async] timeout error
0
0
(I'm pressing lots of keys in those 5 seconds)
There's only one bus, one device, one configuration, one interface and one endpoint.
The endpoint has bmAttributes = 3 which implies I should use interrupt transfers (right?)
so why am I not getting anything? Am I misusing libusb? Do you know a way to do this without libusb?
It's pretty simple actually - when reading from the USB device, you must read exactly the right amount of bytes. You know what that amount is by reading wMaxPacketSize.
Apparently a read request with any other size simply results in a timeout.
Related
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:
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'm trying to open a fullscreen window using SDL2. I've thoroughly looked at the documentation on Display and window management ( https://wiki.libsdl.org/CategoryVideo )... however I don't understand what the best practice would be to get the display resolution I am actually working on.
I have the following sample code:
SDL_DisplayMode mMode;
SDL_Rect mRect;
int ret0 = SDL_GetDisplayBounds(0, &mRect);
std::cout << "bounds w and h are: " << mRect.w << " x " << mRect.h << std::endl;
int ret2 = SDL_GetCurrentDisplayMode(0, &mMode);
std::cout << "current display res w and h are: " << mMode.w << " x " << mMode.h << std::endl;
int ret3 = SDL_GetDisplayMode(0, 0, &mMode);
std::cout << "display mode res w and h are: " << mMode.w << " x " << mMode.h << std::endl;
I am working on a single display that has a resolution of 1920x1080. However, the printed results are:
program output
It seems that SDL_GetDisplayMode() is the only function that displays the correct resolution, so I'd be inclined to use that one. However, I've read that when it comes to SDL_GetDisplayMode(), display modes are sorted according to a certain priority, so that calling it with a 0 returns the largest supported resolution for the display, which is not necessarily the actual resolution (see also: SDL desktop resolution detection in Linux ).
My question is: what is the best practice to obtain the correct resolution?
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.
I have the following system architecture (cannot be changed - legacy code): One main application invokes one or more other applications and these applications interact over a IP protocol.
All applications write to one console window. Unfortunately the console output can get messed up (one character from app 1, next char from app 2, next character from app 4 etc.).
All applications write to console via one Logger.dll (provides static logging functions) using cout/cerr.
Is there a way how I can prevent mixed logging messages in this setup?
Thanks in advance.
EDIT code added:
void Logger::Log(const std::string & componentName, const std::string & Text, LogLevel logLevel, bool logToConsole, bool beep)
{
std::ostringstream stream;
switch (logLevel)
{
case LOG_INFO:
if (logToConsole)
{
stream << componentName << ": INFO " << Text;
mx_console.lock(); // this is a static boost::mutex
std::cout << stream.str() << std::endl;
std::cout.flush();
mx_console.unlock();
}
break;
case LOG_STATUS:
stream << componentName << ": STATUS " << Text;
mx_console.lock();
std::cout << stream.str() << std::endl;
std::cout.flush();
mx_console.unlock();
break;
case LOG_WARNING:
stream << componentName << ": WARNING " << Text;
mx_console.lock();
std::cout << stream.str() << std::endl;
std::cout.flush();
mx_console.unlock();
break;
default:;
}
if (beep)
Beep( 500, 50 );
}
Since you have separate logging functionality you can at minimum use some kind of locking (global mutex, etc.) to avoid interspersing messages from different applications too much. To make it more readable and grepable, add some identifying information, like process name or PID. Wrapping your Logger.dll around existing logging library sounds like an option as well.
Alternatively, you could have logging functions just forward messages to your main application and let that to sort out the synchronization and interspersing.
Syslog might be a solution for you as it is intended to handle logs from various places. Syslog is developed for unix, but this answer shows versions for windows.
You can change your logger to log to syslog instead of the console.
I replaced now all the
std::cout << stream.str();
statements with
std::string str = stream.str();
printf(str.c_str());
and now the output isn't messed up character-wise anymore.
But I don't have a good explanation for this behavior, does anybody know why?