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Re: Serial Console Support in Kernel

On Thu, 12 Jun 2008, Ingo Juergensmann wrote:
> On Thu, Jun 12, 2008 at 03:19:08AM +0200, Michael Schmitz wrote:
> > AFAICS Amiga only offers two options - debug=mem saves the dmesg buffer 
> > in chip RAM for later reading by AmigaOS dmesg. Not too useful for us 
> Indeed, especially at the moment without a suitable monitor at the data
> center. I plan to get one there when I'm visiting my parents the next time. 
> > (Geert: could we leave the corresponding chunk in chipram untouched for 
> > reading it out using a different kernel (or different parameter, like 
> > debug=getmem ??)

Should be possible. Probably the nicest would be to copy the old data
somewhere else, and provide it to the user of the new kernel through sysfs...

> Would be nice to have, yes, but it's difficult to use when there's a
> non-booting kernel and you can't change the commandline remotely to boot
> another kernel. ;) 

One of my wild plans is to get kexec working.  Then you can boot your test
kernel using kexec. If it crashes, just reboot, and the normal bootloader
boots the known-good kernel.

> A real Amiga bootloader with serial console would be really great for this!
> ;)

Hey, amiga-lilo does have serial support!

> > debug=ser is active once consoles have been set up (and it looks like you 
> > should be able to use it as command console as well).
> Well, when the consoles are up you can use the normal serial console as
> well. I don't know what's the difference when you set debug=ser without
> looking it up...  

debug=ser also gives you kernel messages, inclusing early debug
console=ttyS0 gives you `late' kernel messages, plus user space console

> Anyway, it would be nice to have a serial console (system messages during
> boot) as soon as possible and we should setup at least Crest as well for
> using such a serial console. Due to it's VGA output and the FlickerFixer,
> Kullervo don't need this as urgent as Crest and Elgar, IMHO... 

Then you should probably use `debug=ser console=ttyS0', and set up
amiga-lilo to use the serial console.



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

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