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From:   Raul E Rangel <rrangel@chromium.org>
To:     linux-kernel@vger.kernel.org
Cc:     mario.limonciello@amd.com, kramasub@chromium.org,
        Raul E Rangel <rrangel@chromium.org>,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        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: [PATCH] init: Don't proxy console= to earlycon
Date:   Fri,  7 Jul 2023 19:17:25 -0600
Message-ID: <20230707191721.1.Id08823b2f848237ae90ce5c5fa7e027e97c33ad3@changeid>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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.

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
---

 init/main.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/init/main.c b/init/main.c
index aa21add5f7c54..f72bf644910c1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -738,8 +738,7 @@ static int __init do_early_param(char *param, char *val,
 	for (p = __setup_start; p < __setup_end; p++) {
 		if ((p->early && parameq(param, p->str)) ||
 		    (strcmp(param, "console") == 0 &&
-		     strcmp(p->str, "earlycon") == 0)
-		) {
+		     strcmp(p->str, "earlycon") == 0 && val && val[0])) {
 			if (p->setup_func(val) != 0)
 				pr_warn("Malformed early option '%s'\n", param);
 		}
-- 
2.41.0.255.g8b1d071c50-goog