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ACPI: CPPC: Fix enabling CPPC on AMD systems with shared memory

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When commit 72f2ecb7ec ("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 8b356e536e
("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: 72f2ecb7ec ("ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is supported")
Fixes: 8b356e536e ("ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported")
Link: https://lore.kernel.org/all/[email protected]/
Cc: 5.18+ <[email protected]> # 5.18+
Reported-and-tested-by: Oleksandr Natalenko <[email protected]>
Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
This commit is contained in:
Mario Limonciello authored and Rafael J. Wysocki committed 2022-07-13 21:13:14 +02:00
1 parent 32346491dd
commit fbd74d1689
1 file changed
+6
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arch/x86/kernel/acpi/cppc.c
+6
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@@ -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;