13.08.2018 20:52, Alexander Lochmann wrote: > Hi folks! > > We are doing some automatic experiments using FreeBSD running in a > virtual machine. > To control the experiment from the outside, we use serial ports to > communicate with an userspace program. > The communication via serial does work with QEMU. However, it does not > work with BOCHS which is our desired emulator. > Even simple operations like 'echo FOO | tee /dev/ttyu1' or 'cat > /dev/ttyu1' do not work. Both commands block 'forever'. > It does not matter whether we use ttyu0 (file backend) or ttyu1 (tcp > socket). > I put some debug output in sys/dev/uart/uart_dev_ns8250.c. The output > suggests that the driver more or less reads and writes to the serial > ports. At least it does something... > > Do you have any hints how we can further analyze this problem? > Did anyone came across a similar problem?
This could be modem control line "Carrier Detection" (CD) or flow control problem: emulators can have distinct default settings for serial ports. You should not rely on defaults and make sure you disable modem control/CD either explicitly (using stty(1) etc.) or implicitly by switching to /dev/cuau0 instead of /dev/ttyu0. Flow control settings should match too, for both sides of virtual port. _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
