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Subject: Re: [PATCH] printk: Add CONFIG_CONSOLE_LOGLEVEL_PANIC
To:     Petr Mladek <pmladek@suse.com>
Cc:     linux-kernel@vger.kernel.org,
        Dmitry Safonov <0x7f454c46@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        John Ogness <john.ogness@linutronix.de>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>
References: <20210622143350.1105701-1-dima@arista.com>
 <YNWeIks8NC1i2w96@alley> <8e7dae6f-e67c-b961-4986-883e1db0c566@arista.com>
 <YNnD3b1wKfDODKnw@alley>
From:   Dmitry Safonov <dima@arista.com>
Message-ID: <335af380-3bb0-c1c4-ddd5-5c9585d12612@arista.com>
Date:   Mon, 28 Jun 2021 18:26:32 +0100
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On 6/28/21 1:43 PM, Petr Mladek wrote:
[..]
> Is it enough to keep the current level during panic()?

Yes.

> It might be
> easier to introduce a commandline option, for example, no_console_verbose_panic.
> It would do:
> 
> static inline void console_verbose_panic(void)
> {
> 	if (!no_console_verbose_panic)
> 		console_verbose();
> }
> 
> It is clear what it does. On the other hand, the logic with particular
> loglevels is not clear. 3 different proposals has already been mentioned
> in this thread:
> 
> 	if (console_loglevel &&
> 	    (CONFIG_CONSOLE_LOGLEVEL_PANIC > console_loglevel)) {
> 		console_loglevel = CONFIG_CONSOLE_LOGLEVEL_PANIC;
> 	}
> 
> vs.
> 
> 	if (console_loglevel)
> 		console_loglevel = CONFIG_CONSOLE_LOGLEVEL_PANIC;
> 
> vs.
> 
> 	if (console_loglevel && CONFIG_CONSOLE_LOGLEVEL_PANIC)
> 		console_loglevel = CONFIG_CONSOLE_LOGLEVEL_PANIC;
> 
> 
> Just imagine that you are a distributor, developer or admin:
> 
>    What value you would choose for CONFIG_CONSOLE_LOGLEVEL_PANIC?
>    What console loglevel will be used at the end?
> 
> The answer depends on the implemented alhorith, console_loglevel,
> and CONFIG_CONSOLE_LOGLEVEL_PANIC.
> 
> The answer would be much easier if "no_verbose_console_panic" is
> used instead.

Thanks for your replies, Petr, I'll send v2 with the function rename
patch and a patch to introduce this boot option, after the merge window
closes. I appreciate your inputs :-)

Thanks,
          Dmitry