Re: [Xen-devel] Regression in serial console on ia64

[Horms <horms@xxxxxxxxxxxx>]

On Wed, Sep 12, 2007 at 10:19:25AM +0200, Markus Armbruster wrote:
> Horms <horms@xxxxxxxxxxxx> writes:
> 
> > On Tue, Sep 11, 2007 at 02:55:47PM +0200, Markus Armbruster wrote:
> [...]
> >> Kernel messages (printk) go to all registered consoles with flag
> >> CON_ENABLED.
> >> 
> >> User space talks to /dev/console.  The kernel routes that to the
> >> preferred console, which is the last one on the command line, if any,
> >> or else the first one to register (typically the virtual terminal).
> >
> > Hi,
> >
> > Thanks for the help.
> >
> > Previously I had console=tty0 console=ttyS0, which used to work fine
> > but now doesn't. Though perhaps it shouldn't have worked at all.
> >
> > I now have console=ttyS0 only, and everything is working fine.
> >
> > I am guessing that with dual consoles, printk is going to both consoles,
> > but user-space only goes to the first console, as Markus suggests. And I
> 
> The *last* console on the kernel command line!
> 
> > guess that for some reason previously user-space also went to both
> > consoles.
> >
> > I also tried with console=ttyS0 console=tty0, and both printk and
> > in this case user-space does not seem to go to the serial console,
> > perhaps tty0 always wins for some reason?
> 
> tty0 wins because you specified it last.

Currently, neither "console=tty0 console=ttyS0" nor "console=ttyS0
console=tty0" results in user-space getting ttyS0. But having only
"console=ttyS0" gives usespace ttyS0 as its console.

-- 
Horms
  H: http://www.vergenet.net/~horms/
  W: http://www.valinux.co.jp/en/


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