On Tue, Jan 12, 2021 at 6:19 AM Chen Yu <yu.c.c...@intel.com> wrote:
>
> Currently when turbo is disabled(either by BIOS or by the user), the
> intel_pstate driver reads the max non-turbo frequency from the package-wide
> MSR_PLATFORM_INFO(0xce) register. However on asymmetric platforms it is
> possible in theory that small and big core with HWP enabled might have
> different max non-turbo cpu frequency, because the MSR_HWP_CAPABILITIES
> is percpu scope according to Intel Software Developer Manual.
>
> The turbo max freq is already percpu basis in current code, thus make
> similar change to the max non-turbo frequency as well.
>
> Reported-by: Wendy Wang <wendy.w...@intel.com>
> Signed-off-by: Chen Yu <yu.c.c...@intel.com>
> ---
> v2: Per Srinivas' suggestion, avoid duplicated assignment of max_pstate.
> v3: Per Rafael's suggestion, do not add new argument in
> intel_pstate_get_hwp_max()
> to avoid redundant local vars.
> Per Srinivas' suggestion, refined the commit log to reflect the
> 'non-turbo'
> max frequency.
Looks good now, thanks!
Is it needed in -stable and if so, which -stable series should it go into?
> --
> drivers/cpufreq/intel_pstate.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index eaf32ef7a030..99e180f644c3 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -1724,11 +1724,9 @@ static void intel_pstate_max_within_limits(struct
> cpudata *cpu)
> static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
> {
> cpu->pstate.min_pstate = pstate_funcs.get_min();
> - cpu->pstate.max_pstate = pstate_funcs.get_max();
> cpu->pstate.max_pstate_physical = pstate_funcs.get_max_physical();
> cpu->pstate.turbo_pstate = pstate_funcs.get_turbo();
> cpu->pstate.scaling = pstate_funcs.get_scaling();
> - cpu->pstate.max_freq = cpu->pstate.max_pstate * cpu->pstate.scaling;
>
> if (hwp_active && !hwp_mode_bdw) {
> unsigned int phy_max, current_max;
> @@ -1736,9 +1734,12 @@ static void intel_pstate_get_cpu_pstates(struct
> cpudata *cpu)
> intel_pstate_get_hwp_max(cpu, &phy_max, ¤t_max);
> cpu->pstate.turbo_freq = phy_max * cpu->pstate.scaling;
> cpu->pstate.turbo_pstate = phy_max;
> + cpu->pstate.max_pstate =
> HWP_GUARANTEED_PERF(READ_ONCE(cpu->hwp_cap_cached));
> } else {
> cpu->pstate.turbo_freq = cpu->pstate.turbo_pstate *
> cpu->pstate.scaling;
> + cpu->pstate.max_pstate = pstate_funcs.get_max();
> }
> + cpu->pstate.max_freq = cpu->pstate.max_pstate * cpu->pstate.scaling;
>
> if (pstate_funcs.get_aperf_mperf_shift)
> cpu->aperf_mperf_shift = pstate_funcs.get_aperf_mperf_shift();
> --
> 2.17.1
>
