From 7feec7430edddb87c24b0a86b08a03d0b496a755 Mon Sep 17 00:00:00 2001 From: Mario Limonciello Date: Tue, 5 Jul 2022 13:29:14 -0500 Subject: ACPI: CPPC: Only probe for _CPC if CPPC v2 is acked Previously the kernel used to ignore whether the firmware masked CPPC or CPPCv2 and would just pretend that it worked. When support for the USB4 bit in _OSC was introduced from commit 9e1f561afb ("ACPI: Execute platform _OSC also with query bit clear") the kernel began to look at the return when the query bit was clear. This caused regressions that were misdiagnosed and attempted to be solved as part of commit 2ca8e6285250 ("Revert "ACPI: Pass the same capabilities to the _OSC regardless of the query flag""). This caused a different regression where non-Intel systems weren't able to negotiate _OSC properly. This was reverted in commit 2ca8e6285250 ("Revert "ACPI: Pass the same capabilities to the _OSC regardless of the query flag"") and attempted to be fixed by commit c42fa24b4475 ("ACPI: bus: Avoid using CPPC if not supported by firmware") but the regression still returned. These systems with the regression only load support for CPPC from an SSDT dynamically when _OSC reports CPPC v2. Avoid the problem by not letting CPPC satisfy the requirement in `acpi_cppc_processor_probe`. Reported-by: CUI Hao Reported-by: maxim.novozhilov@gmail.com Reported-by: lethe.tree@protonmail.com Reported-by: garystephenwright@gmail.com Reported-by: galaxyking0419@gmail.com Fixes: c42fa24b4475 ("ACPI: bus: Avoid using CPPC if not supported by firmware") Fixes: 2ca8e6285250 ("Revert "ACPI Pass the same capabilities to the _OSC regardless of the query flag"") Link: https://bugzilla.kernel.org/show_bug.cgi?id=213023 Link: https://bugzilla.redhat.com/show_bug.cgi?id=2075387 Reviewed-by: Mika Westerberg Tested-by: CUI Hao Signed-off-by: Mario Limonciello Signed-off-by: Rafael J. Wysocki --- include/linux/acpi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 4f82a5bc6d98..44975c1bbe12 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -584,7 +584,7 @@ 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; +extern bool osc_sb_cppc2_support_acked; extern bool osc_cpc_flexible_adr_space_confirmed; /* USB4 Capabilities */ -- cgit v1.2.3 From 8b356e536e69f3a4d6778ae9f0858a1beadabb1f Mon Sep 17 00:00:00 2001 From: Mario Limonciello Date: Tue, 5 Jul 2022 13:29:15 -0500 Subject: ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported commit 72f2ecb7ece7 ("ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is supported") added support for claiming to support CPPC in _OSC on non-Intel platforms. This unfortunately caused a regression on a vartiety of AMD platforms in the field because a number of AMD platforms don't set the `_OSC` bit 5 or 6 to indicate CPPC or CPPC v2 support. As these AMD platforms already claim CPPC support via a dedicated MSR from `X86_FEATURE_CPPC`, use this enable this feature rather than requiring the `_OSC` on platforms with a dedicated MSR. If there is additional breakage on the shared memory designs also missing this _OSC, additional follow up changes may be needed. Fixes: 72f2ecb7ece7 ("Set CPPC _OSC bits for all and when CPPC_LIB is supported") Reported-by: Perry Yuan Signed-off-by: Mario Limonciello Signed-off-by: Rafael J. Wysocki --- arch/x86/kernel/acpi/cppc.c | 10 ++++++++++ drivers/acpi/cppc_acpi.c | 16 +++++++++++++++- include/acpi/cppc_acpi.h | 1 + 3 files changed, 26 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c index 8b8cbf22461a..734b96454896 100644 --- a/arch/x86/kernel/acpi/cppc.c +++ b/arch/x86/kernel/acpi/cppc.c @@ -11,6 +11,16 @@ /* Refer to drivers/acpi/cppc_acpi.c for the description of functions */ +bool cpc_supported_by_cpu(void) +{ + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + case X86_VENDOR_HYGON: + return boot_cpu_has(X86_FEATURE_CPPC); + } + return false; +} + bool cpc_ffh_supported(void) { return true; diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index d64facbda0fb..6ff1901d7d43 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -577,6 +577,19 @@ bool __weak cpc_ffh_supported(void) return false; } +/** + * cpc_supported_by_cpu() - check if CPPC is supported by CPU + * + * Check if the architectural support for CPPC is present even + * if the _OSC hasn't prescribed it + * + * Return: true for supported, false for not supported + */ +bool __weak cpc_supported_by_cpu(void) +{ + return false; +} + /** * pcc_data_alloc() - Allocate the pcc_data memory for pcc subspace * @@ -686,7 +699,8 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr) if (!osc_sb_cppc2_support_acked) { pr_debug("CPPC v2 _OSC not acked\n"); - return -ENODEV; + if (!cpc_supported_by_cpu()) + return -ENODEV; } /* Parse the ACPI _CPC table for this CPU. */ diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h index c6108581d97d..d389bab54241 100644 --- a/include/acpi/cppc_acpi.h +++ b/include/acpi/cppc_acpi.h @@ -145,6 +145,7 @@ extern bool cppc_allow_fast_switch(void); extern int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data); extern unsigned int cppc_get_transition_latency(int cpu); extern bool cpc_ffh_supported(void); +extern bool cpc_supported_by_cpu(void); extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val); extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val); #else /* !CONFIG_ACPI_CPPC_LIB */ -- cgit v1.2.3