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Peter Anvin" , x86@kernel.org, Jonathan Corbet , Catalin Marinas , Will Deacon , Timur Tabi , graeme.gregory@linaro.org, mark.salter@redhat.com Subject: Re: [PATCH] acpi, spcr: Make SPCR available to x86 Message-ID: <20180212145652.GM25181@hirez.programming.kicks-ass.net> References: <20180118150951.28964-1-prarit@redhat.com> <20180212133429.GC25314@hirez.programming.kicks-ass.net> <1e69fffc-1c3b-8cc0-f1cb-695de5ccdcb5@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1e69fffc-1c3b-8cc0-f1cb-695de5ccdcb5@redhat.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-serial-owner@vger.kernel.org X-Mailing-List: linux-serial@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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?