Re: [RFC PATCH] printk: console: Allow each console to have its own loglevel

From: Chris Down <chris@chrisdown.name>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Petr Mladek <pmladek@suse.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kernel Team <kernel-team@fb.com>
Subject: Re: [RFC PATCH] printk: console: Allow each console to have its own loglevel
Date: Thu, 19 May 2022 15:37:10 +0100	[thread overview]
Message-ID: <YoZWFi0AtmA9fvv/@chrisdown.name> (raw)
In-Reply-To: <CAMuHMdU2tUU6FAM-nK9oxd0GwcO3WwvZp9Um4=w5By+N0P0kXA@mail.gmail.com>

Hey Geert,

Geert Uytterhoeven writes:
>All of the above options are appropriate for "classic" systems,
>where the console device is selected using the "console=" option.
>
>On systems using Device tree, the serial console device is selected
>using the "chosen/stout-path" property in DT, and the graphical
>console is usually auto-detected and auto-enabled through DRM.
>Do you envision a way to specify a specific console loglevel on the
>kernel command line on such systems?

Interesting question! I hadn't really thought about device tree. I actually 
have very little understanding of how it works to be honest :-)

I'm happy to add loglevel support to device tree, I assume I'd add another 
property under the chosen node, like chosen/stdout-loglevel.

I have some questions, though:

1. It looks like DT is standardised. Do I need to get standards approval first?
2. Is there documentation on how to reliably test DT changes?

Thanks!

Chris