On Monday, March 25, 2019 5:04:38 PM CET Srinivas Pandruvada wrote: > The base_frequency display in cpufreq sysfs for intel_pstate gets the > guaranteed ratio by reading CPPC guaranteed performance register as a > first preference before falling back to x86 MSR for Hardware P-state > Capabilities. The current code in cppc_acpi.c assumed that "guaranteed > performance register" can be an integer field, which is invalid as per > ACPI spec. So this change explicitly check for INTEGER values for > invalid BIOS/firmware and ignore. > Also guaranteed performance register field is optional and when not > present, nominal performance can be used as the guaranteed performance. > But spec calls that this is true only in non-autonomous mode. So > no change is made in cppc_acpi.c to make nominal as guaranteed in this > case to avoid dependency on autonomous and non-autonomous mode. Instead > a change is added to intel_pstate driver, which is specific to x86 to > make nominal as guaranteed when guaranteed performance field is absent > or has invalid value. > Also we are working to clarify this non-autonomous mode requirement > through ACPI standard body. > > v2: > Changes done as suggested by Rafael. > > > Srinivas Pandruvada (2): > ACPI / CPPC: Fix processing for guaranteed performance > cpufreq: intel_pstate: Also use cppc nominal_perf for base_frequency > > drivers/acpi/cppc_acpi.c | 9 +++++++-- > drivers/cpufreq/intel_pstate.c | 5 ++++- > 2 files changed, 11 insertions(+), 3 deletions(-) > > Both applied, thanks!
