On Sun, Jun 25, 2017 at 08:44:02PM +0200, Zaerc wrote: > Hello everyone, > > Sorry to bother you, I'll try to keep it brief. I am making an > USB-serial adapter using an Atmel (Microchip) ATMega16u2 with a LUFA > based firmware, which gives me a nice working ttyACM0 device. > > However I am running into some trouble implementing DSR/DTR hardware > flow control. The DTR signal (output) can be set and cleared, no > problem there. The DSR signal (input) however does not seem to get > reported back eventhough with usbmon I can see the device sending it to > the host. Please provide the relevant bits from such a trace (e.g. an interrupt message with some context). > I have mainly tested with gtkterm on a few different (more or less) > recent linux kernels. To add insult to injury (just kidding) it works > on windows (7 tested with RealTerm), so it seems my device should behave > like it is supposed to. I have also tried it with a real serial port > (ttS0, DSR/DTR and RTS/CTS) and an FTDI cable (ttyUSB0, RTS/CTS only) > and gtkterm can see the signals just fine with those. Which is the most recent kernel you've tried? Some changes in this area went into 4.12 (adding support for fragmented notifications), but I guess you haven't tried that yet? Also what is the lsusb -v output for your device? > Any advice, pointers or help you could give me would be greatly > appreciated. And I'd be happy to provide more specific details as it > will be open hard/soft-ware anyway (designed to be made in a fablab by > anyone actually). You should also try enabling debugging for the cdc-acm driver, which may provide a hint about why this isn't working. echo module cdc_acm +p > /sys/kernel/debug/dynamic_debug/control Thanks, Johan -- 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
