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Date:   Mon, 11 Jul 2022 10:32:13 +0200
From:   Petr Mladek <pmladek@suse.com>
To:     John Ogness <john.ogness@linutronix.de>
Cc:     Chris Down <chris@chrisdown.name>, linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>, kernel-team@fb.com
Subject: Re: design: was: Re: [RFC PATCH v2] printk: console: Allow each
 console to have its own loglevel
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References: <YoeQLxhDeIk4VSmx@chrisdown.name>
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 <87o7xz5su4.fsf@jogness.linutronix.de>
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On Fri 2022-07-08 21:10:35, John Ogness wrote:
> On 2022-07-08, Petr Mladek <pmladek@suse.com> wrote:
> > The console-specific loglevel might be set by:
> >
> >   + "console=device,options/loglevel" kernel parameter at boot time
> 
> I ask if we avoid the use of "/loglevel" and instead use a generic
> scheme of:
> 
> console=device,option,option,option
> 
> Of course, it would mean that the type of option would need to be
> specified. Something like:
> 
> console=ttyS0,115200n8,loglevel=3

I like this. It is longer but it makes the meaning very obvious.

I just think about using ':' instead of '=' to distinguish
the assignment of outer 'console' vs the inner 'loglevel' parameters.

It seems to be used in some cases, for example, for ca_keys, crashkernel,
drm.edid_firmware, efi_fake_mem. Even earlyprintk uses it for
bus:device.function.

> The reason why I make such a request is because I would like to be able
> to support disabling threading for certain consoles. Something like:
> 
> console=ttyS0,115200n8,nothread
> 
> or when we have atomic consoles that we can specify that they are always
> used with a "sync" option:
> 
> console=ttyS0,115200n8,sync

Good point.

Best Regards,
Petr