linux-kernel - [PATCH v2 2/2] ACPI: Suppress misleading SPCR console message when SPCR table is absent

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Message-ID: <20250620131309.126555-3-me@linux.beauty>
Date: Fri, 20 Jun 2025 21:13:08 +0800
From: Li Chen <me@...ux.beauty>
To: Hanjun Guo <guohanjun@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Len Brown <lenb@...nel.org>,
	Liu Wei <liuwei09@...tc.cn>,
	Ryan Roberts <ryan.roberts@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jonathan Cameron <Jonathan.Cameron@...wei.com>,
	Sudeep Holla <sudeep.holla@....com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org,
	Anshuman Khandual <anshuman.khandual@....com>,
	Li Chen <chenl311@...natelecom.cn>
Subject: [PATCH v2 2/2] ACPI: Suppress misleading SPCR console message when SPCR table is absent

From: Li Chen <chenl311@...natelecom.cn>

The kernel currently alway prints:
"Use ACPI SPCR as default console: No/Yes "

even on systems that lack an SPCR table. This can
mislead users into thinking the SPCR table exists
on the machines without SPCR.

With this change, the "Yes" is only printed if
the SPCR table is present, parsed and !param_acpi_nospcr.
This avoids user confusion on SPCR-less systems.

Signed-off-by: Li Chen <chenl311@...natelecom.cn>
---
changelog:
v2: refine the printk message logic as suggested by Hanjun Guo.

 arch/arm64/kernel/acpi.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index b9a66fc146c9f..4d529ff7ba513 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -197,6 +197,8 @@ static int __init acpi_fadt_sanity_check(void)
  */
 void __init acpi_boot_table_init(void)
 {
+	int ret;
+
 	/*
 	 * Enable ACPI instead of device tree unless
 	 * - ACPI has been disabled explicitly (acpi=off), or
@@ -250,10 +252,12 @@ void __init acpi_boot_table_init(void)
 		 * behaviour, use acpi=nospcr to disable console in ACPI SPCR
 		 * table as default serial console.
 		 */
-		acpi_parse_spcr(earlycon_acpi_spcr_enable,
+		ret = acpi_parse_spcr(earlycon_acpi_spcr_enable,
 			!param_acpi_nospcr);
-		pr_info("Use ACPI SPCR as default console: %s\n",
-				param_acpi_nospcr ? "No" : "Yes");
+		if (!ret || param_acpi_nospcr || !IS_ENABLED(CONFIG_ACPI_SPCR_TABLE))
+			pr_info("Use ACPI SPCR as default console: No\n");
+		else
+			pr_info("Use ACPI SPCR as default console: Yes\n");
 
 		if (IS_ENABLED(CONFIG_ACPI_BGRT))
 			acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);
-- 
2.49.0