Re: [PATCH v5 2/2] arch/x86: remove pci uart early console from early_prink.c

[Bin Gao <bin.gao@linux.intel.com>]

On Wed, Jun 03, 2015 at 08:35:29AM -0400, Peter Hurley wrote:
> > +/* x86 uses "earlyprintk=xxx", so we keep the compatibility here */
> > +#ifdef CONFIG_X86
> > +static int __init param_setup_earlycon_x86(char *buf)
> > +{
> > +	return param_setup_earlycon(buf);
> > +}
> > +early_param("earlyprintk", param_setup_earlycon_x86);
> 
> I'm concerned that this effectively makes earlyprintk= a synonym for
> earlycon=, which may have unforeseen consequences. I'd rather this
> specifically parse for replacement functionality, ie., only command line
> parameters of the form:
> 
> 	earlyprintk=pciserial,...
> 
> Regards,
> Peter Hurley
> 

Something like this: ?

/*
 * x86 uses "earlyprintk=xxx", so we keep the compatibility here.
 * But we only handle the earlyprintk=uart8250,pci[32]B:D.F[,options] case.
 */
#ifdef CONFIG_X86
static int __init param_setup_earlycon_x86(char *buf)
{
        if (strncmp("uart8250,pci", 12))
                return -EINVAL;
 
        return param_setup_earlycon(buf);
}
early_param("earlyprintk", param_setup_earlycon_x86);

Thanks,
Bin