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 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.
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 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-327388b324997719e86...
Rich.