Re: [PATCH] acpi, spcr: Make SPCR available to x86

Peter Zijlstra
2018-02-12T14:56:53Z

On Mon, Feb 12, 2018 at 08:47:57AM -0500, Prarit Bhargava wrote:
>
>
> On 02/12/2018 08:34 AM, Peter Zijlstra wrote:
> > On Thu, Jan 18, 2018 at 10:09:51AM -0500, Prarit Bhargava wrote:
> >> config ACPI_SPCR_TABLE
> >> + bool "ACPI Serial Port Console Redirection Support"
> >> + default y if X86
> >> + help
> >> + Enable support for Serial Port Console Redirection (SPCR) Table.
> >> + This table provides information about the configuration of the
> >> + earlycon console.
> >
> > I just got asked this by oldconfig, which left me rather puzzled, WTF
> > does this do?
>
> Odd -- I thought I had taken care of that :( My apologies Peter.
>
> ACPI SPCR is used by a vendor to define the serial console for a system. If
> SPCR exists a user can add kernel parameter "earlycon" (no extra kernel
> parameters) and the console will work out-of-the-box.
>
> The serial console configuration varies from vendor to vendor. This takes the
> guess-work out of defining a serial console.

But when I specify "earlyprintk=serial,ttyS0,115200" this SPCR crud will
not interfere?