Commit 6f67e060 authored by Chen Yu's avatar Chen Yu Committed by Rafael J. Wysocki
Browse files

cpufreq: intel_pstate: Get per-CPU max freq via MSR_HWP_CAPABILITIES if available 



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 MSR_HWP_CAPABILITIES is per-CPU scope according
to Intel Software Developer Manual.

The turbo max freq is already per-CPU in current code, so make
similar change to the max non-turbo frequency as well.

Reported-by: default avatarWendy Wang <wendy.wang@intel.com>
Signed-off-by: default avatarChen Yu <yu.c.chen@intel.com>
[ rjw: Subject and changelog edits ]
Cc: 4.18+ <stable@vger.kernel.org> # 4.18+: a45ee4d4: cpufreq: intel_pstate: Change intel_pstate_get_hwp_max() argument
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 597ffbc8

drivers/cpufreq/intel_pstate.c

+3 −2
Original line number Diff line number Diff line
@@ -1714,11 +1714,9 @@ 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;
@@ -1726,9 +1724,12 @@ static void intel_pstate_get_cpu_pstates(struct cpudata *cpu) 
		intel_pstate_get_hwp_max(cpu, &phy_max, &current_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();