This is a note to let you know that I've just added the patch titled
ACPI: bus: Avoid using CPPC if not supported by firmware
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
acpi-bus-avoid-using-cppc-if-not-supported-by-firmwa.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 92d1448c2dea41c86da959246535438499277b94
Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Date: Wed Mar 16 13:39:03 2022 +0100
ACPI: bus: Avoid using CPPC if not supported by firmware
[ Upstream commit c42fa24b44751c62c86e98430ef915c0609a2ab8 ]
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@xxxxxxxxxxxxxx
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Tested-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Acked-by: Huang Rui <ray.huang@xxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Stable-dep-of: 60949b7b8054 ("ACPI: CPPC: Fix MASK_VAL() usage")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 7774b603a7962..9bc5bc5bc359b 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 6dcce036adb9c..02cec9eba937f 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -673,6 +673,9 @@ 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 a23a5aea9c817..42f58a54dff09 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -561,6 +561,7 @@ 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
