This is a note to let you know that I've just added the patch titled ACPI: CPPC: Fix enabling CPPC on AMD systems with shared memory to the 5.18-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-cppc-fix-enabling-cppc-on-amd-systems-with-shared-memory.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fbd74d16890b9f5d08ea69b5282b123c894f8860 Mon Sep 17 00:00:00 2001 From: Mario Limonciello <mario.limonciello@xxxxxxx> Date: Wed, 13 Jul 2022 12:53:46 -0500 Subject: ACPI: CPPC: Fix enabling CPPC on AMD systems with shared memory From: Mario Limonciello <mario.limonciello@xxxxxxx> commit fbd74d16890b9f5d08ea69b5282b123c894f8860 upstream. 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@xxxxxxxxxxxxxx/ Cc: 5.18+ <stable@xxxxxxxxxxxxxxx> # 5.18+ Reported-and-tested-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/acpi/cppc.c | 6 ++++++ 1 file changed, 6 insertions(+) --- 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; Patches currently in stable-queue which might be from mario.limonciello@xxxxxxx are queue-5.18/acpi-cppc-fix-enabling-cppc-on-amd-systems-with-shared-memory.patch queue-5.18/platform-x86-thinkpad-acpi-profile-capabilities-as-i.patch