From: John Ogness <john.ogness@linutronix.de>
To: Esben Haabendal <esben@geanix.com>
Cc: "Petr Mladek" <pmladek@suse.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Sergey Senozhatsky" <senozhatsky@chromium.org>,
linux-rt-users@vger.kernel.org,
"Martin Hundebøll" <martin@geanix.com>
Subject: Re: [PATCH 1/2] printk: export pr_flush()
Date: Tue, 02 Apr 2024 15:29:06 +0206 [thread overview]
Message-ID: <87wmpfq4p1.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <87jzlgf1w2.fsf@geanix.com>
On 2024-04-02, Esben Haabendal <esben@geanix.com> wrote:
>> printk() tries to print directly from the calling context. Are you
>> experiencing problems where you do not see the restarting message?
>
> Yes, that is exactly what we are seing.
>
> It is an i.MX8MP system, and console is attached to ttymxc1
> (drivers/tty/serial/imx.c).
>
> Booting up, and simply executing "reboot" command. Without these two
> patches, the "reboot: Restarting system" message is not written to
> ttymxc1 console. With the patches, it is.
This console driver is using the legacy console interface. For
PREEMPT_RT, legacy consoles run exclusively as a thread and thus may not
have a chance to flush messages before a shutdown/reboot. The correct
solution is to port the driver to the new nbcon console interface.
John Ogness
next prev parent reply other threads:[~2024-04-02 13:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-02 10:10 [PATCH 1/2] printk: export pr_flush() Esben Haabendal
2024-04-02 10:10 ` [PATCH 2/2] reboot: flush printk buffers before final shutdown Esben Haabendal
2024-04-02 10:12 ` Esben Haabendal
2024-04-02 10:13 ` Esben Haabendal
2024-04-02 10:12 ` [PATCH 1/2] printk: export pr_flush() Esben Haabendal
2024-04-02 10:13 ` Esben Haabendal
2024-04-02 10:25 ` John Ogness
2024-04-02 11:19 ` Esben Haabendal
2024-04-02 13:23 ` John Ogness [this message]
2024-04-02 14:41 ` Esben Haabendal
2024-04-02 15:20 ` John Ogness
2024-04-03 9:45 ` Esben Haabendal
2024-04-03 10:09 ` John Ogness
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