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 that to 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 <perry.yuan@xxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
v1->v2:
* Make the code easier to follow (suggested by Rafael)
* Update commit message to reflect this is only fixing the MSR case
and that any other breakage from 72f2ecb7ece7 will need additional
follow ups
drivers/acpi/cppc_acpi.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 903528f7e187..cc154519c608 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -629,7 +629,15 @@ static bool is_cppc_supported(int revision, int num_ent)
return false;
}
- return true;
+ if (!osc_sb_cppc_not_supported)
+ return true;
+
+ pr_debug("Firmware missing _OSC support\n");
+#ifdef CONFIG_X86
+ return boot_cpu_has(X86_FEATURE_CPPC);
+#else
+ return false;
+#endif
}
/*
@@ -684,9 +692,6 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
acpi_status status;
int ret = -ENODATA;
- 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);
--
2.25.1
