From: Petr Mladek <pmladek@suse.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Shreyas Joshi <shreyas.joshi@biamp.com>,
rostedt@goodmis.org, shreyasjoshi15@gmail.com,
linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] printk: handle blank console arguments passed in.
Date: Tue, 6 Oct 2020 18:35:14 +0200 [thread overview]
Message-ID: <20201006163514.GE32369@alley> (raw)
In-Reply-To: <20201006134328.GD32369@alley>
On Tue 2020-10-06 15:43:28, Petr Mladek wrote:
> On Tue 2020-10-06 03:45:00, Guenter Roeck wrote:
> > On 10/6/20 2:52 AM, Petr Mladek wrote:
> > > And it makes perfect sense to disable all consoles or drop all defined
> > > by dts. But I would prefer to make it more obvious way, for
> > > example by parameters like:
> > >
> > > + console=none
> > > + no-console
> > > + no-dtd-console
> > > + no-default-console
> > >
> > Again, the problem isn't limited to dts provided consoles, or at least
> > that was my understanding. I am still trying to understand how default
> > consoles are defined, so I may get something wrong. Anyway, personally I
> > liked "console=", but that is just me. Anything else should work for us
> > as long as it is backward compatible (which excludes the no-xxx options).
>
> Here is my understanding:
>
> The consoles can be defined by scpr, dts, and on the command line. It
> is anyone calling add_preferred_console().
>
> Then the various devices call register_console(). They are registered
> only when they match any console in console_cmdline[] array, see
> try_enable_new_console().
>
> > Whatever is decided, I'd like to have it made official and documented to
> > avoid a similar problem in the future.
Sigh, it is even bigger mess than I expected. There is a magic
variable "console_set_on_cmdline". It used, for example, in
of_console_check() to prevent using the default console from dts.
It is used on few more locations to prevent the default console.
But there are other locations when add_preferred_console() is
called without checking this variable.
As a result, "console=" has different effect on different systems.
I tend to revert the problematic patch now.
And I would try to clean up this mess for-5.11. There is a big chance
that people used the empty console= only on systems where it disabled
all default consoles. I would try to make it the official global
behavior. But this would need some longer testing in linux-next, ...
Best Regards,
Petr
next prev parent reply other threads:[~2020-10-06 16:35 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 5:29 [PATCH] printk: handle blank console arguments passed in Shreyas Joshi
2020-03-17 1:34 ` Shreyas Joshi
2020-03-17 1:39 ` Steven Rostedt
2020-03-17 2:01 ` Sergey Senozhatsky
2020-03-17 2:17 ` Shreyas Joshi
2020-03-17 8:22 ` Sergey Senozhatsky
2020-05-22 6:46 ` Shreyas Joshi
2020-05-22 6:53 ` Shreyas Joshi
2020-05-22 10:00 ` Petr Mladek
2020-10-06 2:59 ` Sergey Senozhatsky
2020-10-06 3:35 ` Guenter Roeck
2020-10-06 5:08 ` Greg Kroah-Hartman
2020-10-06 11:17 ` Guenter Roeck
2020-10-06 6:59 ` Sergey Senozhatsky
2020-10-06 9:54 ` Petr Mladek
2020-10-06 13:33 ` Sergey Senozhatsky
2020-10-06 14:22 ` Guenter Roeck
2020-10-06 16:08 ` Sergey Senozhatsky
2020-10-06 9:52 ` Petr Mladek
2020-10-06 10:45 ` Guenter Roeck
2020-10-06 13:43 ` Petr Mladek
2020-10-06 16:35 ` Petr Mladek [this message]
2020-10-06 17:15 ` Sergey Senozhatsky
2020-10-07 7:28 ` Petr Mladek
2020-10-07 12:30 ` Sergey Senozhatsky
2020-10-07 14:39 ` Sergey Senozhatsky
2020-10-07 15:57 ` Guenter Roeck
2020-10-07 16:29 ` Sergey Senozhatsky
2020-10-08 5:52 ` Sergey Senozhatsky
2020-10-08 9:01 ` Petr Mladek
2020-10-08 10:56 ` Sergey Senozhatsky
2020-10-08 12:05 ` Sergey Senozhatsky
2020-10-22 11:38 ` Petr Mladek
2020-10-22 13:32 ` Sergey Senozhatsky
2020-10-08 8:50 ` Petr Mladek
2020-10-08 12:20 ` Sergey Senozhatsky
2020-10-08 12:37 ` Sergey Senozhatsky
2020-05-15 15:24 ` Petr Mladek
2020-05-20 11:50 ` Sergey Senozhatsky
2020-05-22 6:40 ` Shreyas Joshi
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