Hi, greg I have used the minicom program which calls the open system call in blocking mode to access the usb device, and it seems there is no problem with it. So, the only thing I can suspect is that there is a bug in "open" system call implementation. Do you know which directory containing the source code about the implementation of "open" system call in the linux kernel tree? sincerely loki 2013/10/27 Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > > On Fri, Oct 25, 2013 at 08:21:58AM +0000, loki wrote: > > Hi, > > > > I used the USB-serial driver option.c to communicate with the GSM modem > > device through usb, the used host controller is EHCI. The problem is that > > nothing appear on the screen when type characters after using "microcom -s > > 115200 /dev/ttyUSB3" command to access the ttyUSB3 device node. > > It sounds like microcom is not setting up the proper tty line settings > for the device, as you say if you run it in "blocking" mode, it works > properly, right? > > What about using the "normal" programs to connect to this device (i.e. > network/modem manager and the like?) Don't they work properly with the > hardware here? > > thanks, > > greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
