linux-kernel - Re: [PATCH] powerpc/crash: Allow direct printing on kexec

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Message-ID: <20241021144403.8429-1-ryotkkr98@gmail.com>
Date: Mon, 21 Oct 2024 14:44:03 +0000
From: Ryo Takakura <ryotkkr98@...il.com>
To: john.ogness@...utronix.de
Cc: christophe.leroy@...roup.eu,
	hbathini@...ux.ibm.com,
	leobras.c@...il.com,
	linux-kernel@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org,
	maddy@...ux.ibm.com,
	mpe@...erman.id.au,
	naveen@...nel.org,
	npiggin@...il.com,
	pmladek@...e.com,
	ryotkkr98@...il.com,
	sourabhjain@...ux.ibm.com
Subject: Re: [PATCH] powerpc/crash: Allow direct printing on kexec

On 2024-10-21, John Ogness <john.ogness@...utronix.de> wrote:
>On 2024-10-21, Ryo Takakura <ryotkkr98@...il.com> wrote:
>>> Rather than removing the deferring, it would be better to convert the
>>> console you are using to the new NBCON API. Then it would be able to
>>> print direct and safe during panic. (printk_deferred does not affect
>>> NBCON consoles.) What console driver are you using that you want to
>>> see the messages on?
>>
>> I was working on qemu ppc64 this time but I am usually working on 
>> Raspberry Pi 4 (mostly for fun and study) which uses either of 
>> bcm2835-aux-uart or amba-pl011. It would be really nice to see them 
>> working as nbcon!
>> I am thinking of taking a look at [0] but If there were any other 
>> references, I would really like to look into as well.
>>
>> [0] https://lore.kernel.org/lkml/87wn3zsz5x.fsf@jogness.linutronix.de/
>
>The lastest version of the series is here [1]. The series is still
>undergoing revisions, however the changes are 8250-specific. The API for
>nbcon consoles is already available since 6.12-rc1. You are certainly
>welcome to try to convert one of those Raspi 4 drivers to the nbcon
>interface. I would be happy to review it.

Thanks for sharing!
I will take a look at it and definitley give a try!

>John Ogness

Sincerely,
Ryo Takakura