From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
John Ogness <john.ogness@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Guenter Roeck <linux@roeck-us.net>,
Shreyas Joshi <shreyas.joshi@biamp.com>,
shreyasjoshi15@gmail.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] printk/console: Allow to disable console output by using console="" or console=null
Date: Thu, 12 Nov 2020 08:59:18 +0900 [thread overview]
Message-ID: <X6x61h58ZvRgyTQR@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <20201111135450.11214-3-pmladek@suse.com>
On (20/11/11 14:54), Petr Mladek wrote:
> The commit 48021f98130880dd74 ("printk: handle blank console arguments
> passed in.") prevented crash caused by empty console= parameter value.
>
> Unfortunately, this value is widely used on Chromebooks to disable
> the console output. The above commit caused performance regression
> because the messages were pushed on slow console even though nobody
> was watching it.
>
> Use ttynull driver explicitly for console="" and console=null
> parameters. It has been created for exactly this purpose.
>
> It causes that preferred_console is set. As a result, ttySX and ttyX
> are not used as a fallback. And only ttynull console gets registered by
> default.
>
> It still allows to register other consoles either by additional console=
> parameters or SPCR. It prevents regression because it worked this way even
> before. Also it is a sane semantic. Preventing output on all consoles
> should be done another way, for example, by introducing mute_console
> parameter.
>
> Link: https://lore.kernel.org/r/20201006025935.GA597@jagdpanzerIV.localdomain
> Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
-ss
next prev parent reply other threads:[~2020-11-12 1:36 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 13:54 [PATCH 0/2] printk/console: Use ttynull when no console is available or wanted Petr Mladek
2020-11-11 13:54 ` [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console Petr Mladek
2020-11-11 16:36 ` Greg Kroah-Hartman
2020-11-11 22:52 ` Guenter Roeck
2020-11-11 23:58 ` Sergey Senozhatsky
2020-11-12 0:17 ` Sergey Senozhatsky
2020-11-12 1:45 ` Sergey Senozhatsky
2020-11-16 16:20 ` Petr Mladek
2021-01-06 23:36 ` ARC no console output (was Re: [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console) Vineet Gupta
2021-01-06 23:36 ` Vineet Gupta
2021-01-06 23:36 ` [Buildroot] " Vineet Gupta
2021-01-07 9:02 ` John Ogness
2021-01-07 9:02 ` John Ogness
2021-01-07 13:14 ` Greg Ungerer
2021-01-07 13:14 ` Greg Ungerer
2021-01-07 16:43 ` Vineet Gupta
2021-01-07 16:43 ` Vineet Gupta
2021-01-07 16:43 ` [Buildroot] " Vineet Gupta
2021-01-07 17:04 ` Petr Mladek
2021-01-07 17:04 ` Petr Mladek
2021-01-07 17:58 ` Vineet Gupta
2021-01-07 17:58 ` Vineet Gupta
2021-01-07 17:58 ` [Buildroot] " Vineet Gupta
2021-01-08 3:48 ` Sergey Senozhatsky
2021-01-08 3:48 ` Sergey Senozhatsky
2021-01-08 5:18 ` Vineet Gupta
2021-01-08 5:18 ` Vineet Gupta
2021-01-08 5:18 ` [Buildroot] " Vineet Gupta
2021-01-08 9:30 ` Petr Mladek
2021-01-08 9:30 ` Petr Mladek
2021-01-13 22:07 ` Peter Korsgaard
2021-01-13 22:07 ` Peter Korsgaard
2021-01-13 22:07 ` [Buildroot] " Peter Korsgaard
2021-01-07 9:09 ` Richard Weinberger
2021-01-07 9:09 ` Richard Weinberger
2021-01-07 12:48 ` Petr Mladek
2021-01-07 12:48 ` Petr Mladek
2021-01-07 15:27 ` [Buildroot] " Yann E. MORIN
2021-01-07 15:27 ` Yann E. MORIN
2021-01-07 15:27 ` Yann E. MORIN
2020-11-11 13:54 ` [PATCH 2/2] printk/console: Allow to disable console output by using console="" or console=null Petr Mladek
2020-11-11 22:52 ` Guenter Roeck
2020-11-11 23:59 ` Sergey Senozhatsky [this message]
2020-11-20 14:24 ` [PATCH 0/2] printk/console: Use ttynull when no console is available or wanted Petr Mladek
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