Re: [patch] early printk and boot console fixups.

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On 5/16/07, Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
> On Tuesday 15 May 2007 10:17:50 pm Yinghai Lu wrote:
> > for early_uart_console, I have some ideas:
> > 1. merged that into early_serial_console in
> > arch/x86_64/kernel/early_printk.c, and
> > move early_printk.c to kernel/, --- make it understand
> >      earlyprintk=uart,io,0x3f8,9600n8
> >      earlyprintk=uart,mmio,0xff5e0000,115200n8
> > in addition to vga, ttyS, serial
>
> I would rather try to merge 8250_early and early_printk.
> "console=uart,io,0x3f8" is already pretty similar to
> "earlyprintk=serial", and it would be nice to have only one.
>
> "console=uart" does have the disadvantage that you have to know the
> port address.  But it has the advantage that it doesn't depend on
> compiled-in legacy serial port names.  If you need early console
> output, you're probably a developer and can come up with the address.
>
> I think it would be nice to have a "console=vga".  That could use
> the current "earlyprintk=vga" implementation, and automatically
> hand off to tty0.
>
> Then we could remove "earlyprintk=" and always use "console=uart"
> or "console=vga".

earlyprintk= is needed for seeting bootconsole, or setting CON_BOOT,
and it is could be loaded earlier with early_param than console_init.

in the console_init (via register_console), the console is handed over
from bootconsole to normal console.

also console_init could be moved to quite late than current, and till
some subsystem is initialized like pci and usb.

YH