Hi Carlo, On Nov 10 10:07, Carlo B. wrote: > Hello, > into winsup/cygwin/fhandler/serial.cc, the function > fhandler_serial::switch_modem_lines() is called when TIOCMBIS/TIOCMBIC > are used into an ioctl() call. > This function uses EscapeCommFunction() for setting and resetting RTS > and DTR signals of a serial port. > Unfortunately, this function does not work on USB CDC devices. > This is not a true bug of a CYGWIN but an issue of the usbser.sys > driver from Microsoft, from Windows 2000 to the latest Windows 11. > Both 32bit and 64bit versions of the operating system are affected. > Actually, I tested EscapeCommFunction() also when using a real UART, > based on the traditional 16550 driver and it works fine. > Using thirdy party CDC drivers, like the one provided by FTDI for > their USB bridge chips, probably also works. > However, it is also possible to drive the RTS/DTR signals by writing > their state with SetCommState(), which proved to be working fine all > types of connection. > > Here, I attached a patch that I made for fixing this issue.
Thanks for your patch, but would you be so kind to create a complete git patch, created by committing your patch locally on top of git master, with a fine commit message outlining the technical details as described above? Then create a patch file using `git format-patch -1' and send it here or to the cygwin-patches mailing list, please? > I was wondering if this fix could be imported into the core of CYGWIN > and if it could be possible to include it also into the v3.3.x branch, > since I have seen that 32bit support has been removed from Master > branch recently. There will be no more 32 bit release. 3.3.6 is the last one. Thanks, Corinna -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
