[AMD Official Use Only - General] Hi Rafael: > -----Original Message----- > From: Limonciello, Mario <Mario.Limonciello@xxxxxxx> > Sent: Tuesday, June 28, 2022 12:59 AM > To: Limonciello, Mario <Mario.Limonciello@xxxxxxx>; Rafael J. Wysocki > <rafael@xxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; Pierre Gondois > <pierre.gondois@xxxxxxx>; Sudeep Holla <sudeep.holla@xxxxxxx> > Cc: Yuan, Perry <Perry.Yuan@xxxxxxx>; linux-acpi@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: [PATCH] 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 > `X86_FEATURE_CPPC`, use this enable this feature rather than requiring the > `_OSC`. > > 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> > --- > drivers/acpi/cppc_acpi.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index > 903528f7e187..5463e6309b9a 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -629,6 +629,15 @@ static bool is_cppc_supported(int revision, int > num_ent) > return false; > } > > + if (osc_sb_cppc_not_supported) { > + pr_debug("Firmware missing _OSC support\n"); #ifdef > CONFIG_X86 > + return boot_cpu_has(X86_FEATURE_CPPC); #else > + return false; > +#endif > + } > + > return true; > } > I align with Mario to use his patch to fix the amd pstate driver loading failure issue. AMD CPUID include the cppc flag to mark the CPPC valid if the _OSC dose not have the CPPC support info added. Tested-by: Perry Yuan <perry.yuan@xxxxxxx> > @@ -684,9 +693,6 @@ 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); > -- > 2.34.1