Re: [PATCH]serial: make early_uart to use early_prarm instead of console_initcall

[Andi Kleen <ak@suse.de>]

On Sun, May 20, 2007 at 08:23:32PM -0700, Andrew Morton wrote:
> On Fri, 18 May 2007 19:00:16 -0700 Yinghai Lu <Yinghai.Lu@Sun.COM> wrote:
> 
> > [PATCH]serial: make early_uart to use early_prarm instead of console_initcall
> > 
> > Make early_uart to use early_param, so uart console can be used earlier.
> > Make it to be bootconsole with CON_BOOT flag, so can use console handover
> > feature. and it will switch to corresponding normal serial console automatically.
> > new command line will be
> > 
> > earlycon=uart,io,0x3f8,9600n8
> > earlycon=uart,io,0x3f8,9600n8 console=tty0
> > 
> > it will print in very early stage
> > Early serial console at I/O port 0x3f8 (options '9600n8')
> > later for console it will print
> > console handover: boot [uart0] -> real [ttyS0]
> 
> I'll queue this up for some testing, but I'd be a bit reluctant to send it
> into Linus due to my poor understanding of what it actually does.  What
> _is_ an early console, and how does it differ from a non-early one?

It is someone's reimplemention of earlyprintk= for another architecture
that happens to mostly work on x86 too because the code is not ifdeffed. 
I don't think it makes much sense on x86 though because earlyprintk exists.

-Andi