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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Linux ACPI <linux-acpi@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	x86 Maintainers <x86@kernel.org>,
	linux-rtc@vger.kernel.org,
	Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: [PATCH v1 6/8] x86: rtc: Drop PNP device check
Date: Mon, 23 Feb 2026 16:31:49 +0100	[thread overview]
Message-ID: <8660687.T7Z3S40VBb@rafael.j.wysocki> (raw)
In-Reply-To: <5983325.DvuYhMxLoT@rafael.j.wysocki>

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

Previous changes effectively prevented PNP devices from being created
for the CMOS RTC on x86 with ACPI.

Although in principle a CMOS RTC PNP device may exist on an x86 system
without ACPI (that is, an x86 system where there is no ACPI at all, not
one booted with ACPI disabled), such systems were there in the field ~30
years ago and most likely they would not be able to run a contemporary
Linux kernel.

For the above reasons, drop the PNP device check from add_rtc_cmos().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 arch/x86/kernel/rtc.c | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index b112178e8185..314b062a15de 100644
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -6,7 +6,6 @@
 #include <linux/platform_device.h>
 #include <linux/mc146818rtc.h>
 #include <linux/export.h>
-#include <linux/pnp.h>
 
 #include <asm/vsyscall.h>
 #include <asm/x86_init.h>
@@ -134,19 +133,6 @@ static struct platform_device rtc_device = {
 
 static __init int add_rtc_cmos(void)
 {
-#ifdef CONFIG_PNP
-	static const char * const ids[] __initconst =
-	    { "PNP0b00", "PNP0b01", "PNP0b02", };
-	struct pnp_dev *dev;
-	int i;
-
-	pnp_for_each_dev(dev) {
-		for (i = 0; i < ARRAY_SIZE(ids); i++) {
-			if (compare_pnp_id(dev->id, ids[i]) != 0)
-				return 0;
-		}
-	}
-#endif
 	if (cmos_rtc_platform_device_present)
 		return 0;
 
@@ -154,8 +140,7 @@ static __init int add_rtc_cmos(void)
 		return -ENODEV;
 
 	platform_device_register(&rtc_device);
-	dev_info(&rtc_device.dev,
-		 "registered platform RTC device (no PNP device found)\n");
+	dev_info(&rtc_device.dev, "registered fallback platform RTC device\n");
 
 	return 0;
 }
-- 
2.51.0





  parent reply	other threads:[~2026-02-23 15:33 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-23 15:27 [PATCH v1 0/8] ACPI: x86/rtc-cmos: Bind rtc-cmos to platform devices Rafael J. Wysocki
2026-02-23 15:28 ` [PATCH v1 1/8] ACPI: x86: cmos_rtc: Clean up address space handler driver Rafael J. Wysocki
2026-02-23 15:28 ` [PATCH v1 2/8] ACPI: x86: cmos_rtc: Improve coordination with ACPI TAD driver Rafael J. Wysocki
2026-02-23 15:29 ` [PATCH v1 3/8] ACPI: x86: cmos_rtc: Create a CMOS RTC platform device Rafael J. Wysocki
2026-02-25 18:01   ` Dave Hansen
2026-02-23 15:30 ` [PATCH v1 4/8] ACPI: x86/rtc-cmos: Use platform device for driver binding Rafael J. Wysocki
2026-02-26 13:01   ` Alexandre Belloni
2026-03-03  6:07   ` Nathan Chancellor
2026-03-03 12:51     ` Rafael J. Wysocki
2026-03-03 17:52       ` Nathan Chancellor
2026-03-03 18:47         ` Rafael J. Wysocki
2026-03-03 21:17           ` Nathan Chancellor
2026-03-04 12:42             ` Rafael J. Wysocki
2026-02-23 15:31 ` [PATCH v1 5/8] ACPI: PNP: Drop CMOS RTC PNP device support Rafael J. Wysocki
2026-02-23 15:31 ` Rafael J. Wysocki [this message]
2026-02-25 18:01   ` [PATCH v1 6/8] x86: rtc: Drop PNP device check Dave Hansen
2026-02-25 18:10     ` Rafael J. Wysocki
2026-02-23 15:32 ` [PATCH v1 7/8] rtc: cmos: Drop PNP device support Rafael J. Wysocki
2026-02-26 13:02   ` Alexandre Belloni
2026-02-23 15:33 ` [PATCH v1 8/8] ACPI: TAD/x86: cmos_rtc: Consolidate address space handler setup Rafael J. Wysocki

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