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Date:   Sat, 8 Jul 2023 17:48:32 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Raul E Rangel <rrangel@chromium.org>
Cc:     linux-kernel@vger.kernel.org, mario.limonciello@amd.com,
        kramasub@chromium.org, Alexander Potapenko <glider@google.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Li Zhe <lizhe.67@bytedance.com>,
        "Liam R. Howlett" <Liam.Howlett@Oracle.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Will Deacon <will@kernel.org>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Zhou jie <zhoujie@nfschina.com>
Subject: Re: [PATCH] init: Don't proxy console= to earlycon
Message-Id: <20230708174832.0af1d974cf67805dfc8ad655@linux-foundation.org>
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On Fri,  7 Jul 2023 19:17:25 -0600 Raul E Rangel <rrangel@chromium.org> wrote:

> Right now we are proxying the `console=XXX` command line args to the
> param_setup_earlycon. This is done because the following are
> equivalent:
> 
>     console=uart[8250],mmio,<addr>[,options]
>     earlycon=uart[8250],mmio,<addr>[,options]
> 
> In addition, when `earlycon=` or just `earlycon` is specified on the
> command line, we look at the SPCR table or the DT to extract the device
> options.
> 
> When `console=` is specified on the command line, it's intention is to
> disable the console. Right now since we are proxying the `console=`
> flag to the earlycon handler, we enable the earlycon_acpi_spcr_enable
> variable when an SPCR table is present. This means that we
> inadvertently enable the earlycon.
> 
> This change makes it so we only proxy the console= command if it's
> value is not empty. This way we can correctly handle both cases.
> 

I hope someone understands this ;)

Please "grep -r earlycon Documentation" and check for suitable places
to update our documentation.