On Wed, Jul 13, 2022 at 7:54 PM Mario Limonciello mario.limonciello@amd.com wrote:
When commit 72f2ecb7ece7 ("ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is supported") was introduced, we found collateral damage that a number of AMD systems that supported CPPC but didn't advertise support in _OSC stopped having a functional amd-pstate driver. The _OSC was only enforced on Intel systems at that time.
This was fixed for the MSR based designs by commit 8b356e536e69f ("ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported") but some shared memory based designs also support CPPC but haven't advertised support in the _OSC. Add support for those designs as well by hardcoding the list of systems.
Fixes: 72f2ecb7ece7 ("ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is supported") Fixes: 8b356e536e69f ("ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported") Link: https://lore.kernel.org/all/3559249.JlDtxWtqDm@natalenko.name/ Cc: stable@vger.kernel.org # 5.18 Reported-and-tested-by: Oleksandr Natalenko oleksandr@natalenko.name Signed-off-by: Mario Limonciello mario.limonciello@amd.com
arch/x86/kernel/acpi/cppc.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c index 734b96454896..8d8752b44f11 100644 --- a/arch/x86/kernel/acpi/cppc.c +++ b/arch/x86/kernel/acpi/cppc.c @@ -16,6 +16,12 @@ bool cpc_supported_by_cpu(void) switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: case X86_VENDOR_HYGON:
if (boot_cpu_data.x86 == 0x19 && ((boot_cpu_data.x86_model <= 0x0f) ||(boot_cpu_data.x86_model >= 0x20 && boot_cpu_data.x86_model <= 0x2f)))return true;else if (boot_cpu_data.x86 == 0x17 &&boot_cpu_data.x86_model >= 0x70 && boot_cpu_data.x86_model <= 0x7f)return true; return boot_cpu_has(X86_FEATURE_CPPC); } return false;--
Applied as 5.19-rc material, thanks!