[PATCH 1/3][SRU][J] ACPI: bus: Avoid using CPPC if not supported by firmware

[Ivan Hu]

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

BugLink: https://bugs.launchpad.net/bugs/2006077

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 at intel.com>
Tested-by: Mario Limonciello <mario.limonciello at amd.com>
Acked-by: Huang Rui <ray.huang at amd.com>
Reviewed-by: Mika Westerberg <mika.westerberg at linux.intel.com>
(cherry picked from commit c42fa24b44751c62c86e98430ef915c0609a2ab8)
Signed-off-by: Ivan Hu <ivan.hu at canonical.com>
---
 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 7774b603a796..9bc5bc5bc359 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 091a16aaf822..14ad7d6fa701 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -668,6 +668,9 @@ 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 6224b1e32681..c4d476dccfa9 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -560,6 +560,7 @@ 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
-- 
2.25.1