linux-kernel - Re: [PATCH] x86/acpi: Add acpi=spcr to use SPCR-provided default console

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20260115120058.GCaWjW-sT7eBr94SEr@fat_crate.local>
Date: Thu, 15 Jan 2026 13:00:58 +0100
From: Borislav Petkov <bp@...en8.de>
To: Shenghao Yang <me@...nghaoyang.info>
Cc: x86@...nel.org, Jonathan Corbet <corbet@....net>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Len Brown <lenb@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH] x86/acpi: Add acpi=spcr to use SPCR-provided default
 console

On Thu, Jan 15, 2026 at 01:09:40AM +0800, Shenghao Yang wrote:
> We've been inserting the dumped config into the kernel command 
> line and rebooting on first boot (e.g. console=uart,io,0x3f8,115200),
> but would love to avoid this loop.

Yah, put that in your v2 pls. That's much more understandable.

> It's easier this way for larger fleets - we don't want to manage
> hardware specific serial console settings on the kernel command line
> if the firmware is already capable of telling us the correct ones.

Should also be in the commit message.

> If earlycon is specified on the command line the console from SPCR
> is used, but only as a boot console. It's not present in
> /proc/consoles.
> 
> It is possible to retain it with keep_bootcon, but that uses the
> less efficient (in the 8250 case) 8250_early driver.

Also for the commit message.

> In 0231d00082f6 ("ACPI: SPCR: Make SPCR available to x86") the SPCR
> console is only added as an option for earlycon but not as an ordinary
> console so users don't see console output changes.  
> 
> The patch adds an opt in so we can get the SPCR console added as
> an ordinary console.

Yap, your explanations make much more sense, thanks.

Please structure your v2 something like this boilerplate guidance below:

1. Prepare the context for the explanation briefly.

2. Explain the problem at hand.

3. "It happens because of <...>"

4. "Fix it by doing X"

5. "(Potentially do Y)."

And some of those above are optional depending on the issue being
explained.

For more detailed info, see
Documentation/process/submitting-patches.rst,
Section "2) Describe your changes".

Also, to the tone, from Documentation/process/submitting-patches.rst:

 "Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
  instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
  to do frotz", as if you are giving orders to the codebase to change
  its behaviour."

Also, do not talk about what your patch does - that should (hopefully) be
visible from the diff itself. Rather, talk about *why* you're doing what
you're doing.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette