linux-kernel - [PATCH v1 1/3] cpufreq: intel_pstate: Add and use hybrid_get_cpu

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Message-ID: <4692569.LvFx2qVVIh@rafael.j.wysocki>
Date: Wed, 08 Oct 2025 20:55:38 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, Lukasz Luba <lukasz.luba@....com>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 Dietmar Eggemann <dietmar.eggemann@....com>,
 Christian Loehle <christian.loehle@....com>
Subject:
 [PATCH v1 1/3] cpufreq: intel_pstate: Add and use hybrid_get_cpu_type()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Introduce a function for identifying the type of a given CPU in a
hybrid system, called hybrid_get_cpu_type(), and use if for hybrid
scaling factor determination in hwp_get_cpu_scaling().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/cpufreq/intel_pstate.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -912,6 +912,11 @@ static struct freq_attr *hwp_cpufreq_att
 	[HWP_CPUFREQ_ATTR_COUNT] = NULL,
 };

+static u8 hybrid_get_cpu_type(unsigned int cpu)
+{
+	return cpu_data(cpu).topo.intel_type;
+}
+
 static bool no_cas __ro_after_init;

 static struct cpudata *hybrid_max_perf_cpu __read_mostly;
@@ -2298,18 +2303,14 @@ static int knl_get_turbo_pstate(int cpu)
 static int hwp_get_cpu_scaling(int cpu)
 {
 	if (hybrid_scaling_factor) {
-		struct cpuinfo_x86 *c = &cpu_data(cpu);
-		u8 cpu_type = c->topo.intel_type;
-
 		/*
 		 * Return the hybrid scaling factor for P-cores and use the
 		 * default core scaling for E-cores.
 		 */
-		if (cpu_type == INTEL_CPU_TYPE_CORE)
+		if (hybrid_get_cpu_type(cpu) == INTEL_CPU_TYPE_CORE)
 			return hybrid_scaling_factor;

-		if (cpu_type == INTEL_CPU_TYPE_ATOM)
-			return core_get_scaling();
+		return core_get_scaling();
 	}

 	/* Use core scaling on non-hybrid systems. */