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From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Linux PM <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Subject: Re: [PATCH v1] cpufreq: intel_pstate: Set non-turbo capacity to HWP_GUARANTEED_PERF()
Date: Tue, 7 Jul 2026 13:47:11 -0700	[thread overview]
Message-ID: <20260707204711.GA1255@ranerica-svr.sc.intel.com> (raw)
In-Reply-To: <12928972.O9o76ZdvQC@rafael.j.wysocki>

On Tue, Jul 07, 2026 at 07:19:55PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Setting cpu->capacity_perf to cpu->pstate.max_pstate_physical in the
> "no turbo" case is inconsistent with what happens elsewhere in the
> driver and causes arch_scale_cpu_capacity() to be incorrect.  It also
> skews arch_scale_freq_capacity() which ends up differing from 1024 for
> the guaranteed P-state.
> 
> Address that by setting capacity_perf to HWP_GUARANTEED_PERF() in the
> "no turbo" case.

Indeed, using cpu->pstate.max_pstate_physical does not make sense. It only
reflects what PLATFORM_INFO[15:8] says for _all_ CPUs, regardless of type,
resized by cpu->pstate.scaling/cpu->pstate.perf_ctl_scaling. No relation
to any property of the CPU.

Now arch_scale_freq_capacity() looks correct.

> 
> Fixes: 929ebc93ccaa ("cpufreq: intel_pstate: Set asymmetric CPU capacity on hybrid systems")
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Tested-by Ricardo Neri <ricardo.neri-calderon@linux.intel.com>

      reply	other threads:[~2026-07-07 20:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-07 17:19 [PATCH v1] cpufreq: intel_pstate: Set non-turbo capacity to HWP_GUARANTEED_PERF() Rafael J. Wysocki
2026-07-07 20:47 ` Ricardo Neri [this message]

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