cpufreq: intel_pstate: Always use HWP_DESIRED_PERF in passive mode

JIRA: https://issues.redhat.com/browse/RHEL-110833

commit 1cefe49
Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date:   Mon Jun 16 20:19:19 2025 +0200

    cpufreq: intel_pstate: Always use HWP_DESIRED_PERF in passive mode

    In the passive mode, intel_cpufreq_update_pstate() sets HWP_MIN_PERF in
    accordance with the target frequency to ensure delivering adequate
    performance, but it sets HWP_DESIRED_PERF to 0, so the processor has no
    indication that the desired performance level is actually equal to the
    floor one.  This may cause it to choose a performance point way above
    the desired level.

    Moreover, this is inconsistent with intel_cpufreq_adjust_perf() which
    actually sets HWP_DESIRED_PERF in accordance with the target performance
    value.

    Address this by adjusting intel_cpufreq_update_pstate() to pass
    target_pstate as both the minimum and the desired performance levels
    to intel_cpufreq_hwp_update().

    Fixes: a365ab6 ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback")
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Tested-by: Shashank Balaji <shashank.mahadasyam@sony.com>
    Link: https://patch.msgid.link/6173276.lOV4Wx5bFT@rjwysocki.net

Signed-off-by: Steve Best <sbest@redhat.com>

Author: sfbest

drivers/cpufreq/intel_pstate.c

@@ -3260,8 +3260,8 @@ static int intel_cpufreq_update_pstate(struct cpufreq_policy *policy,
 		int max_pstate = policy->strict_target ?
 					target_pstate : cpu->max_perf_ratio;
 
-		intel_cpufreq_hwp_update(cpu, target_pstate, max_pstate, 0,
-					 fast_switch);
+		intel_cpufreq_hwp_update(cpu, target_pstate, max_pstate,
+					 target_pstate, fast_switch);
 	} else if (target_pstate != old_pstate) {
 		intel_cpufreq_perf_ctl_update(cpu, target_pstate, fast_switch);
 	}