Thomas Klausner <t...@giga.or.at> writes: > I wanted to look at the serial console of a second machine, so I > plugged in a USB serial dongle into my NetBSD (7.99.38/amd64): > > uftdi0 at uhub4 port 3 > uftdi0: FTDI FT232R USB UART, rev 2.00/6.00, addr 3 > ucom0 at uftdi0 portno 1
Beware the the word floating around on the Interwebs is that there are a lot of counterfeit FTDI chipsets out there. Apparently they mostly work, and the angst is around how official binary FTDI drivers behave. Probably this is not your issue. > Then I looked at ucom(4) and saw that the first mentioned entry is > /dev/dtyU?, so I set up 'minicom -s' using that device. Then I > connected using minicom. The screen stayed empty, and the process was > unkillable. I also tried 'cu -l /dev/dtyU0' which had the same result. > (Even though there should have been something visible on the serial > line.) dtyU0 is the right file. ttyU0 and dtyU0 are for the same device, but dty is a dialout device that does not block waiting for carrier detect, vs tty that by default blocks opening until CD is asserted. (Back when I was young, we had 300 baud modems, with dialin from terminals and dialout for uucp!) I've done what you describe with usb/serial dongles, often with uplcom. > At the same time, the USB keyboard and USB mouse stopped working, > without anything visible in dmesg. > > I wanted other processes to finish before rebooting, so I waited. > > 4 hours later I saw the following in the kernel log: > ehci_sync_hc: cv_timedwait() = 35 > > 4 hours later I tried rebooting, but had to press the reset button, > 'shutdown -r' didn't work. > > Should I have used /dev/ttyU0 instead? > > I find it worrying that the USB mouse and keyboard stopped working > without any kernel messages, and that the processes hung unkillably. I think you are running into either really serious bugs in our kernel, or a broken device that is causing way more trouble than it should Did you remove the serial dongle? I have found that at times, pulling a troublesome USB device resolves things. Did you try on a netbsd-7 system?
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