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

From: Prarit Bhargava
Date: Mon Feb 12 2018 - 08:48:09 EST




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.

P.

>