Date: Thu, 12 May 2016 10:26:16 -0700 From: bob prohaska <fbsd@www.zefox.net> To: freebsd-arm@freebsd.org Subject: Re: Serial console trouble on RPI2 Message-ID: <20160512172616.GD1049@www.zefox.net> In-Reply-To: <20160510163828.GA1049@www.zefox.net> References: <20160510163828.GA1049@www.zefox.net>
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It looks like the problem is with USB: After rebooting the Pi on the USB end cu runs but no connection results: root@www:/home/bob # cu -l cuaU0 -s 115200 [carriage returns echo, but no login prompt] [next, unplug and re-plug the usb connector] cu: unsupported speed 115200 root@www:/home/bob # [try cu again] root@www:/home/bob # cu -l cuaU0 -s 115200 Connected FreeBSD/arm (www.zefox.net) (ttyu0) login: [now all works as expected] Any ideas how to fix this? The message about unsupported speed suggests a configuration error, but in single user I don't think /etc/ttys or /etc/gettytab comes into play. Thanks for reading and any suggestions, bob prohaska On Tue, May 10, 2016 at 09:38:28AM -0700, bob prohaska wrote: > In trying to set up serial consoles on a quartet of RPI2 hosts > two of the machine's consoles worked without explicit changes. > The other two don't seem to work. If anybody can give me a hint > what's wrong it would be much appreciated. > > The USB-serial adapters are these, using PL2303 chips: > Btek® WINDOWS 8 Supported Debug Cable for > Raspberry Pi USB Programming USB to TTL Serial Cable > > First, two RPI2s were set up with cross-connected consoles, so each > provided serial access to the other. The setup worked without any issues. > > Next, all four hosts were arranged in a ring, with each host providing serial > port access to the next in the ring. The two hosts which had working serial > consoles in the first place continue to present a serial console to the monitoring > host. The others do not, even after reboot. Here's an example: > > On the monitoring host: > root@ns2:/home/bob # cu -l cuaU0 -s 115200 > > Connected > ? > > The monitored host was rebooted via the network. It came back up in good order, > but nothing appeared on the serial port. The kernel configs of all hosts are > the same, dmesg on one "no console" machine reports in part: > FreeBSD 11.0-CURRENT #6 r292479: Sun Dec 20 07:09:08 PST 2015 > ..... > uart0: <PrimeCell UART (PL011)> mem 0x201000-0x201fff irq 65 on simplebus0 > uart0: console (115200,n,8,1) > > In this particular case I can see the wires on the GPIO header and they're > in the right place. The USB-serial adapter is new out of the sealed box, > so it seems unlikely to be defective. > > The one difference among the hosts is FreeBSD revision number. The hosts > which offer usable serial consoles are r292412 and r299225, the two which > don't are r292479 and r297367. All four kernel config files contain: > # Comment following lines for boot console on serial port > device vt > device kbdmux > device ukbd > which seems backwards but causes no trouble in two of the machines. > > Any guidance appreciated! > > Thanks for reading, > > bob prohaska > >
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