linux-kernel - [PATCH v6 1/6] ACPI: CPPC: enable AMD CPPC V2 support for family 17h processors

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Date: Thu, 8 Feb 2024 11:46:28 +0800
From: Perry Yuan <perry.yuan@....com>
To: <rafael.j.wysocki@...el.com>, <Mario.Limonciello@....com>,
	<viresh.kumar@...aro.org>, <Ray.Huang@....com>, <gautham.shenoy@....com>,
	<Borislav.Petkov@....com>
CC: <Alexander.Deucher@....com>, <Xinmei.Huang@....com>,
	<Xiaojian.Du@....com>, <Li.Meng@....com>, <linux-pm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH v6 1/6] ACPI: CPPC: enable AMD CPPC V2 support for family 17h processors

As there are some AMD processors which only support CPPC V2 firmware and
BIOS implementation, the amd_pstate driver will be failed to load when
system booting with below kernel warning message:

[    0.477523] amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

To make the amd_pstate driver can be loaded on those TR40 processors, it
needs to match x86_model from 0x30 to 0x7F for family 17H.
With the change, the system can load amd_pstate driver as expected.

Reviewed-by: Mario Limonciello <mario.limonciello@....com>
Reported-by: Gino Badouri <badouri.g@...il.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218171
Fixes: fbd74d1689 ("ACPI: CPPC: Fix enabling CPPC on AMD systems with shared memory")
Signed-off-by: Perry Yuan <perry.yuan@....com>
---
 arch/x86/kernel/acpi/cppc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
index 8d8752b44f11..ff8f25faca3d 100644
--- a/arch/x86/kernel/acpi/cppc.c
+++ b/arch/x86/kernel/acpi/cppc.c
@@ -20,7 +20,7 @@ bool cpc_supported_by_cpu(void)
 		    (boot_cpu_data.x86_model >= 0x20 && boot_cpu_data.x86_model <= 0x2f)))
 			return true;
 		else if (boot_cpu_data.x86 == 0x17 &&
-			 boot_cpu_data.x86_model >= 0x70 && boot_cpu_data.x86_model <= 0x7f)
+			 boot_cpu_data.x86_model >= 0x30 && boot_cpu_data.x86_model <= 0x7f)
 			return true;
 		return boot_cpu_has(X86_FEATURE_CPPC);
 	}
-- 
2.34.1