From c42fa24b44751c62c86e98430ef915c0609a2ab8 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Wed, 16 Mar 2022 13:39:03 +0100
Subject: [PATCH] ACPI: bus: Avoid using CPPC if not supported by firmware
Git-commit: c42fa24b44751c62c86e98430ef915c0609a2ab8
Patch-mainline: v5.18-rc1
References: bsc#1199793
If the platform firmware indicates that it does not support CPPC by
clearing the OSC_SB_CPC_SUPPORT and OSC_SB_CPCV2_SUPPORT bits in the
platform _OSC capabilities mask, avoid attempting to evaluate _CPC
which may fail in that case.
Because the OSC_SB_CPC_SUPPORT and OSC_SB_CPCV2_SUPPORT bits are only
added to the supported platform capabilities mask on x86, when
X86_FEATURE_HWP is supported, allow _CPC to be evaluated regardless
in the other cases.
Link: https://lore.kernel.org/linux-acpi/CAJZ5v0i=ecAksq0TV+iLVObm-=fUfdqPABzzkgm9K6KxO1ZCcg@mail.gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/acpi/bus.c | 8 ++++++++
drivers/acpi/cppc_acpi.c | 3 +++
include/linux/acpi.h | 1 +
3 files changed, 12 insertions(+)
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index c7670d441ad9..8aa7860602e7 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -283,6 +283,8 @@ EXPORT_SYMBOL_GPL(osc_pc_lpi_support_confirmed);
bool osc_sb_native_usb4_support_confirmed;
EXPORT_SYMBOL_GPL(osc_sb_native_usb4_support_confirmed);
+bool osc_sb_cppc_not_supported;
+
static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
static void acpi_bus_osc_negotiate_platform_control(void)
{
@@ -338,6 +340,12 @@ static void acpi_bus_osc_negotiate_platform_control(void)
return;
}
+#ifdef CONFIG_X86
+ if (boot_cpu_has(X86_FEATURE_HWP))
+ osc_sb_cppc_not_supported = !(capbuf_ret[OSC_SUPPORT_DWORD] &
+ (OSC_SB_CPC_SUPPORT | OSC_SB_CPCV2_SUPPORT));
+#endif
+
/*
* Now run _OSC again with query flag clear and with the caps
* supported by both the OS and the platform.
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 866560cbb082..3e89ad246b60 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -656,6 +656,9 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
acpi_status status;
int ret = -EFAULT;
+ if (osc_sb_cppc_not_supported)
+ return -ENODEV;
+
/* Parse the ACPI _CPC table for this CPU. */
status = acpi_evaluate_object_typed(handle, "_CPC", NULL, &output,
ACPI_TYPE_PACKAGE);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 6274758648e3..690b0533104a 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -580,6 +580,7 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context);
extern bool osc_sb_apei_support_acked;
extern bool osc_pc_lpi_support_confirmed;
extern bool osc_sb_native_usb4_support_confirmed;
+extern bool osc_sb_cppc_not_supported;
/* USB4 Capabilities */
#define OSC_USB_USB3_TUNNELING 0x00000001
--
2.35.3