linux-kernel - [PATCH v1 7/8] ACPI: bus: Adjust feature mask creation for \_SB.

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Message-ID: <9564052.CDJkKcVGEf@rafael.j.wysocki>
Date: Thu, 18 Dec 2025 21:41:42 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Linux ACPI <linux-acpi@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Linux PCI <linux-pci@...r.kernel.org>, Bjorn Helgaas <helgaas@...nel.org>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 Hans de Goede <hansg@...nel.org>,
 Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH v1 7/8] ACPI: bus: Adjust feature mask creation for \_SB._OSC

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

The feature mask creation for \_SB._OSC platform features is messy
and hard to follow, so clean it up and make all of the CPPC-related
features depend on CONFIG_ACPI_CPPC_LIB as they will not work if it
is not set anyway.

Also make acpi_bus_osc_negotiate_platform_control() print a message
including a bit mask representing the features for which control has
been granted.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/bus.c |   83 ++++++++++++++++++++++++-----------------------------
 1 file changed, 39 insertions(+), 44 deletions(-)

--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -418,73 +418,68 @@ bool osc_sb_cppc2_support_acked;
 static void acpi_bus_osc_negotiate_platform_control(void)
 {
 	static const u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
-	u32 capbuf[2];
+	u32 capbuf[2], feature_mask;
 	struct acpi_buffer cap = {
 		.pointer = capbuf,
 		.length = sizeof(capbuf),
 	};
 	acpi_handle handle;
 
-	capbuf[OSC_SUPPORT_DWORD] = OSC_SB_PR3_SUPPORT; /* _PR3 is in use */
+	feature_mask = OSC_SB_PR3_SUPPORT | OSC_SB_HOTPLUG_OST_SUPPORT |
+			OSC_SB_PCLPI_SUPPORT | OSC_SB_OVER_16_PSTATES_SUPPORT |
+			OSC_SB_GED_SUPPORT | OSC_SB_IRQ_RESOURCE_SOURCE_SUPPORT;
+
+	if (IS_ENABLED(CONFIG_ARM64) || IS_ENABLED(CONFIG_X86))
+		feature_mask |= OSC_SB_GENERIC_INITIATOR_SUPPORT;
+
+	if (IS_ENABLED(CONFIG_ACPI_CPPC_LIB)) {
+		feature_mask |= OSC_SB_CPC_SUPPORT | OSC_SB_CPCV2_SUPPORT |
+				OSC_SB_CPC_FLEXIBLE_ADR_SPACE;
+		if (IS_ENABLED(CONFIG_SCHED_MC_PRIO))
+			feature_mask |= OSC_SB_CPC_DIVERSE_HIGH_SUPPORT;
+	}
+
 	if (IS_ENABLED(CONFIG_ACPI_PROCESSOR_AGGREGATOR))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PAD_SUPPORT;
+		feature_mask |= OSC_SB_PAD_SUPPORT;
+
 	if (IS_ENABLED(CONFIG_ACPI_PROCESSOR))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PPC_OST_SUPPORT;
+		feature_mask |= OSC_SB_PPC_OST_SUPPORT;
+
 	if (IS_ENABLED(CONFIG_ACPI_THERMAL))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_FAST_THERMAL_SAMPLING_SUPPORT;
+		feature_mask |= OSC_SB_FAST_THERMAL_SAMPLING_SUPPORT;
+
 	if (IS_ENABLED(CONFIG_ACPI_BATTERY))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_BATTERY_CHARGE_LIMITING_SUPPORT;
+		feature_mask |= OSC_SB_BATTERY_CHARGE_LIMITING_SUPPORT;
 
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT;
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PCLPI_SUPPORT;
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_OVER_16_PSTATES_SUPPORT;
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_GED_SUPPORT;
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_IRQ_RESOURCE_SOURCE_SUPPORT;
 	if (IS_ENABLED(CONFIG_ACPI_PRMT))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PRM_SUPPORT;
-	if (IS_ENABLED(CONFIG_ACPI_FFH))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_FFH_OPR_SUPPORT;
-
-#ifdef CONFIG_ARM64
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_GENERIC_INITIATOR_SUPPORT;
-#endif
-#ifdef CONFIG_X86
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_GENERIC_INITIATOR_SUPPORT;
-#endif
-
-#ifdef CONFIG_ACPI_CPPC_LIB
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_CPC_SUPPORT;
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_CPCV2_SUPPORT;
-#endif
+		feature_mask |= OSC_SB_PRM_SUPPORT;
 
-	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_CPC_FLEXIBLE_ADR_SPACE;
-
-	if (IS_ENABLED(CONFIG_SCHED_MC_PRIO))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_CPC_DIVERSE_HIGH_SUPPORT;
+	if (IS_ENABLED(CONFIG_ACPI_FFH))
+		feature_mask |= OSC_SB_FFH_OPR_SUPPORT;
 
 	if (IS_ENABLED(CONFIG_USB4))
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_NATIVE_USB4_SUPPORT;
+		feature_mask |= OSC_SB_NATIVE_USB4_SUPPORT;
 
 	if (!ghes_disable)
-		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_APEI_SUPPORT;
+		feature_mask |= OSC_SB_APEI_SUPPORT;
+
 	if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
 		return;
 
+	capbuf[OSC_SUPPORT_DWORD] = feature_mask;
+
 	if (acpi_osc_handshake(handle, sb_uuid_str, 1, &cap))
 		return;
 
-#ifdef CONFIG_ACPI_CPPC_LIB
-	osc_sb_cppc2_support_acked = capbuf[OSC_SUPPORT_DWORD] & OSC_SB_CPCV2_SUPPORT;
-#endif
-
-	osc_sb_apei_support_acked =
-			capbuf[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
-	osc_pc_lpi_support_confirmed =
-			capbuf[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
-	osc_sb_native_usb4_support_confirmed =
-			capbuf[OSC_SUPPORT_DWORD] & OSC_SB_NATIVE_USB4_SUPPORT;
-	osc_cpc_flexible_adr_space_confirmed =
-			capbuf[OSC_SUPPORT_DWORD] & OSC_SB_CPC_FLEXIBLE_ADR_SPACE;
+	feature_mask = capbuf[OSC_SUPPORT_DWORD];
+
+	acpi_handle_info(handle, "platform _OSC feature mask [%08x]\n", feature_mask);
+
+	osc_sb_cppc2_support_acked = feature_mask & OSC_SB_CPCV2_SUPPORT;
+	osc_sb_apei_support_acked = feature_mask & OSC_SB_APEI_SUPPORT;
+	osc_pc_lpi_support_confirmed = feature_mask & OSC_SB_PCLPI_SUPPORT;
+	osc_sb_native_usb4_support_confirmed = feature_mask & OSC_SB_NATIVE_USB4_SUPPORT;
+	osc_cpc_flexible_adr_space_confirmed = feature_mask & OSC_SB_CPC_FLEXIBLE_ADR_SPACE;
 }
 
 /*