linux-kernel - Re: [PATCH] printk: Make CONSOLE_LOGLEVEL

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Message-ID: <20180620110335.sjzmtra2z3chvon2@pathway.suse.cz>
Date:   Wed, 20 Jun 2018 13:03:35 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] printk: Make CONSOLE_LOGLEVEL_QUIET configurable

On Tue 2018-06-19 13:57:26, Hans de Goede wrote:
> The goal of passing the "quiet" option to the kernel is for the kernel
> to be quiet unless something really is wrong.
> 
> Sofar passing quiet has been (mostly) equivalent to passing
> loglevel=4 on the kernel commandline. Which means to show any messages
> with a level of KERN_ERR or higher severity on the console.
> 
> In practice this often does not result in a quiet boot though, since
> there are many false-positive or otherwise harmless error messages printed,
> defeating the purpose of the quiet option. Esp. the ACPICA code is really
> bad wrt this, but there are plenty of others too.

I see your pain. But this sounds like a workaround for a broken code.
This change might just encourage people to create even more mess.

> This commit makes CONSOLE_LOGLEVEL_QUIET configurable.
> 
> This for example will allow distros which want quiet to really mean quiet
> to set CONSOLE_LOGLEVEL_QUIET so that only messages with a higher severity
> then KERN_ERR (CRIT, ALERT, EMERG) get printed, avoiding an endless game
> of whack-a-mole silencing harmless error messages.

I find it a bit confusing that "quiet" would mean something different
on different systems.

Why did not you use loglevel=<whatever_you_need> instead of "quiet"?

Alternative solution would be to add "silent" or so to calm down
everything. But I am afraid that any change in this area would
just create a mess similar to grep -s and -q options.

Best Regards,
Petr

PS: I will not block it if Steven and Sergey are fine with this. But
I want to be sure that they considered the above views. It looked like
a no-brainer to me at the beginning. I even pushed this to printk.git.
But the pushing gave me some more time to think about it...