Messages in this thread | | | Date | Thu, 03 Jan 2008 13:43:33 +0100 | From | devzero@web ... | Subject | Re: serial console _after_ boot ? - was: Redirect kernel console |
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hi !
i was wondering how to make kernel messages appear on /dev/ttyS0 without a reboot, i.e. kernelparam "console=ttyS0"
after playing for a while with setconsole, setterm and klogconsole i didn`t find a way to make that happen.
i can do "setconsole /dev/tty1 </dev/console" and then "echo test >/dev/console" and see "test" on tty1
"setterm -msg on -msglevel 8 >/dev/console" (or >/dev/tty1), modprobe loop;rmmod loop - and i see the kernel message there
i can do "setconsole /dev/ttyS0 </dev/console" and then "echo test >/dev/console" and see "test" on ttyS0
BUT :
"setterm -msg on -msglevel 8 >/dev/console" (or >/dev/ttyS0), modprobe loop;rmmod loop ...... nothing!
since i came across jan`s posting from 2005, which didn`t get a reply i think it`s not that stupid to ask again...
any clue how to do that at runtime or what`s the issue here ? (see excerpts below)
i can set regards roland
List: linux-kernel Subject: Redirect kernel console From: Jan Engelhardt <jengelh () linux01 ! gwdg ! de> Date: 2005-08-13 12:48:22 Message-ID: Pine.LNX.4.61.0508131447220.4457 () yvahk01 ! tjqt ! qr [Download message RAW]
Hi,
there is a klogconsole utiltity that allows to change the console to which kernel messages are printed. However, is it possible to redirect to ttyS0 without a reboot?
Jan Engelhardt -------
>> Subject: Re: serial console _after_ boot ?
>> > Setterm outputs the correct escape sequences to stdout. You can >> > configure another tty using 'setterm -msglevel 8 -msg on > /dev/ttyS0'. >> > I tested this on the standard kernel consoles (/dev/tty1-9), and it >> > worked. You obviously need root access to write the escape sequences to >> > the tty's. >> >> oh - yes, this works! but with tty1-9 only. >> not with ttyS0 :( > >.....as the docs tell..... > > Some options however (marked "virtual consoles only" below) do not correspond to a terminfo(5) capability. > > -msg [on|off] (virtual consoles only) > Enables or disables the sending of kernel printk() messages to the console. > > -msglevel 1-8 (virtual consoles only) > Sets the console logging level for kernel printk() messages. All messages strictly more important than this > will be printed, so a logging level of 0 has the same effect as -msg on and a logging level of 8 will print > all kernel messages. klogd(8) may be a more convenient interface to the logging of kernel messages.
> > > but i don`t have change_console. > > > searched the net and found that this eventually should be part of sysvinit package. > > > but mine doesn`t provide that tool. > > > > > > found "setconsole" which looks like something similar, but "setconsole /dev/ttyS0 < /dev/console" > > > doesn`t have any effect > > > > What distribution do you use? I have change_console on gentoo, yet I > > cannot find the tool on a debian etch. But that's a vserver, so it's > > probably not a reference. > > i have opensuse 10.3
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