Kanwar Ranbir Sandhu
2007-Jul-09 12:19 UTC
[Fedora-xen] ups connected to serial port, but can''t communicate via ttyS0
Hi, I tried to use ttyS0 in dom0 for a serial interface UPS, but apcupsd complains that it can''t talk to ttyS0. I look through /var/log/messages, and sure enough, xen is using it: Jul 3 09:45:22 xenmaster kernel: Xen virtual console successfully installed as ttyS0 Can that be turned off, so that ttyS0 isn''t used by Xen? I tried to do this several months ago, but back then I was told Fedora was working towards fixing the serial port access problems. Regards, Ranbir -- Kanwar Ranbir Sandhu Linux 2.6.20-1.2962.fc6 i686 GNU/Linux 08:15:36 up 5 days, 20:58, 3 users, load average: 0.35, 0.18, 0.17
Richard W.M. Jones
2007-Jul-09 12:56 UTC
Re: [Fedora-xen] ups connected to serial port, but can''t communicate via ttyS0
Kanwar Ranbir Sandhu wrote:> Hi, > > I tried to use ttyS0 in dom0 for a serial interface UPS, but apcupsd > complains that it can''t talk to ttyS0. I look through /var/log/messages, > and sure enough, xen is using it: > > Jul 3 09:45:22 xenmaster kernel: Xen virtual console successfully > installed as ttyS0 > > Can that be turned off, so that ttyS0 isn''t used by Xen? I tried to do > this several months ago, but back then I was told Fedora was working > towards fixing the serial port access problems.Try the suggestions here: http://phaq.phunsites.net/2007/06/30/xen-console-grabbded-devttys0/ In particular try booting with xencons=off (on the kernel command line, not the Xen hypervisor command line). Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903
Kanwar Ranbir Sandhu
2007-Jul-09 17:26 UTC
Re: [Fedora-xen] ups connected to serial port, but can''t communicate via ttyS0
On Mon, 2007-07-09 at 13:56 +0100, Richard W.M. Jones wrote:> Try the suggestions here: > > http://phaq.phunsites.net/2007/06/30/xen-console-grabbded-devttys0/ > > In particular try booting with xencons=off (on the kernel command line, > not the Xen hypervisor command line).That worked! My Smart UPS 1400 is now being monitored/controlled from dom0 with apcupsd. There were some errors in /var/log/messages, though: Jul 9 12:50:45 xenmaster kernel: serial8250: ttyS0 at I/O 0x3f8 (irq 4) is a 16550A Jul 9 12:50:45 xenmaster kernel: 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A Jul 9 12:55:02 xenmaster kernel: Kernel command line: ro root=/dev/vg00/root xencons=tty1 Jul 9 12:55:11 xenmaster kernel: WARNING: Failed to register Xen virtual console driver as ''tty1'' Jul 9 12:55:14 xenmaster kernel: serial8250: ttyS0 at I/O 0x3f8 (irq 4) is a 16550A Jul 9 12:55:14 xenmaster kernel: 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A I''ll try with a different tty later, say tty6. But, I don''t know if that will fix the above warning. I have another question: can I hand the serial port to a domU, or does it have to be present in dom0? Regards, Ranbir -- Kanwar Ranbir Sandhu Linux 2.6.20-1.2962.fc6 i686 GNU/Linux 13:24:02 up 6 days, 2:06, 4 users, load average: 0.20, 0.35, 0.26
Richard W.M. Jones
2007-Jul-09 17:58 UTC
Re: [Fedora-xen] ups connected to serial port, but can''t communicate via ttyS0
Kanwar Ranbir Sandhu wrote:> On Mon, 2007-07-09 at 13:56 +0100, Richard W.M. Jones wrote: >> Try the suggestions here: >> >> http://phaq.phunsites.net/2007/06/30/xen-console-grabbded-devttys0/ >> >> In particular try booting with xencons=off (on the kernel command line, >> not the Xen hypervisor command line). > > That worked! My Smart UPS 1400 is now being monitored/controlled from > dom0 with apcupsd. > > There were some errors in /var/log/messages, though: > > Jul 9 12:50:45 xenmaster kernel: serial8250: ttyS0 at I/O 0x3f8 (irq > 4) is a 16550A > Jul 9 12:50:45 xenmaster kernel: 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is > a 16550A > Jul 9 12:55:02 xenmaster kernel: Kernel command line: ro > root=/dev/vg00/root xencons=tty1 > Jul 9 12:55:11 xenmaster kernel: WARNING: Failed to register Xen > virtual console driver as ''tty1'' > Jul 9 12:55:14 xenmaster kernel: serial8250: ttyS0 at I/O 0x3f8 (irq > 4) is a 16550A > Jul 9 12:55:14 xenmaster kernel: 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is > a 16550A > > I''ll try with a different tty later, say tty6. But, I don''t know if > that will fix the above warning.It''s absolutely ages since I used serial ports under Linux -- I mean 10 years at least -- but my recollection is that they are called things like ttyS1 (with the ''S'' in there).> I have another question: can I hand the serial port to a domU, or does > it have to be present in dom0?There''s a bit about this on the Xen wiki: http://wiki.xensource.com/xenwiki/InstallationNotes#head-327388b324997719e864f8740fed06036c799e38 Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903