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Date:   Fri, 6 May 2022 08:43:02 +0200
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Subject: Re: [PATCH printk v5 1/1] printk: extend console_lock for
 per-console locking
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To:     John Ogness <john.ogness@linutronix.de>,
        Petr Mladek <pmladek@suse.com>
Cc:     Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-amlogic@lists.infradead.org
From:   Marek Szyprowski <m.szyprowski@samsung.com>
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Precedence: bulk

Hi John,

On 06.05.2022 00:33, John Ogness wrote:
> On 2022-05-05, John Ogness <john.ogness@linutronix.de> wrote:
>> I will go through and check if all access to AML_UART_CONTROL is
>> protected by port->lock.
> The startup() callback of the uart_ops is not called with the port
> locked. I'm having difficulties identifying if the startup() callback
> can occur after the console was already registered via meson_uart_init()
> and could be actively printing, but I see other serial drivers are
> protecting their registers in the startup() callback with the
> port->lock.
>
> Could you try booting the meson hardware with the following change? (And
> removing any previous debug changes I posted?)

Bingo! It looks that the startup() is called when getty initializes 
console. This fixed the issues observed on the Amlogic Meson based boards.

Feel free to add:

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland