Re: [PATCH -v3] x86: Setup early console as early as possible

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 03 Aug 2010 00:14:38 -0700 Yinghai Lu <yinghai@kernel.org> wrote:

> 
> Analyze "console=uart8250,io,0x3f8,115200n8" in i386_start_kernel/x86_64_start_kernel,
> and call setup_early_serial8250_console() to init early serial console.
> 
> only can handle io port kind of 8250. because mmio need ioremap.
> 
> -v2: use boot_params.hdr.version instead of adding another variable, Suggested by hpa
>      update after using x86 memblock patchset
> -v3: x86 memblock can not make into with 2.6.36 now
>      so update this patch to be applied before x86 memblock patchset again.
> 
> ...
>
> --- linux-2.6.orig/kernel/printk.c
> +++ linux-2.6/kernel/printk.c
> @@ -1203,6 +1203,10 @@ void register_console(struct console *ne
>  	if (console_drivers && newcon->flags & CON_BOOT) {
>  		/* find the last or real console */
>  		for_each_console(bcon) {
> +			/* not again */
> +			if (bcon == newcon)
> +				return;
> +
>  			if (!(bcon->flags & CON_BOOT)) {
>  				printk(KERN_INFO "Too late to register bootconsole %s%d\n",

Why this change?