From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> 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> --- drivers/acpi/bus.c | 8 ++++++++ drivers/acpi/cppc_acpi.c | 3 +++ include/linux/acpi.h | 1 + 3 files changed, 12 insertions(+) Index: linux-pm/drivers/acpi/bus.c =================================================================== --- linux-pm.orig/drivers/acpi/bus.c +++ linux-pm/drivers/acpi/bus.c @@ -284,6 +284,8 @@ EXPORT_SYMBOL_GPL(osc_pc_lpi_support_con 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) { @@ -339,6 +341,12 @@ static void acpi_bus_osc_negotiate_platf 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. Index: linux-pm/drivers/acpi/cppc_acpi.c =================================================================== --- linux-pm.orig/drivers/acpi/cppc_acpi.c +++ linux-pm/drivers/acpi/cppc_acpi.c @@ -656,6 +656,9 @@ int acpi_cppc_processor_probe(struct acp 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); Index: linux-pm/include/linux/acpi.h =================================================================== --- linux-pm.orig/include/linux/acpi.h +++ linux-pm/include/linux/acpi.h @@ -580,6 +580,7 @@ acpi_status acpi_run_osc(acpi_handle han 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
