From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout03.his.huawei.com (canpmsgout03.his.huawei.com [113.46.200.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EAFF031F986; Tue, 3 Mar 2026 12:03:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772539424; cv=none; b=IfeLgut4hZ3iHxrWOa3044oKyoYCrPVX5OxfWVbyE65gNTkilthrRTAdHuqWXp0f+7Xk0IVIj76150f+N8y/TVC9+YpDi/nQwChphvMquciMeZIkDYsAjA8xGh1OGEiizzcSzIY4fOZnsPIbmO0O2K64OZuOeDAWTqhPEOAeGSw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772539424; c=relaxed/simple; bh=TqatppKJ8/sSOqaB9V9U7v66SprShwvtMtSnJwrs7sU=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=e5bqKU5hZ+UiRZ5QzK4WxJtJyPtHybuEwWqnub9W1qJf151TsBKi/OTjvmKFz9qTazV+8f904pfdRhFo8XysTh7hwDGH4VK9mEKkCqyjx+4iCo7kodVHQdrEISefrYOLWx2G5C75hOpHuZyZu0vAjQWrVwvwkwP4H+p3ocGe2BM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=k689BAgV; arc=none smtp.client-ip=113.46.200.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="k689BAgV" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=T1z2JGVSris9ggGYp/iPgLJUtlSMEdRWvCGyzfP+AsA=; b=k689BAgVLs9sJv29hSwiJuvaJnZbjp5h76i2RVrl0drHggP6H3BUz+no7zijMwoF0BN4/M7zi 5Gbgre3iHaRtL5muO+im4aitazEw0S6TSH357aMixgyVj+uIhIS/WXIcjNJ742pRd45sfCLjA8q 7Cf3Ev6ugXrxgAHRVWkILIY= Received: from mail.maildlp.com (unknown [172.19.162.197]) by canpmsgout03.his.huawei.com (SkyGuard) with ESMTPS id 4fQDpp243XzpStt; Tue, 3 Mar 2026 19:58:42 +0800 (CST) Received: from kwepemr200004.china.huawei.com (unknown [7.202.195.241]) by mail.maildlp.com (Postfix) with ESMTPS id 2645F40569; Tue, 3 Mar 2026 20:03:40 +0800 (CST) Received: from [10.67.121.62] (10.67.121.62) by kwepemr200004.china.huawei.com (7.202.195.241) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 3 Mar 2026 20:03:39 +0800 Message-ID: <54f5795f-2c0b-49f2-a319-216c17657c0f@huawei.com> Date: Tue, 3 Mar 2026 20:03:38 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] cpufreq: cppc: Clamp default minimum limit to lowest_nonlinear_perf To: , CC: , , , , , , , , , References: <20260213100633.15413-1-zhangpengjie2@huawei.com> From: "zhangpengjie (A)" In-Reply-To: <20260213100633.15413-1-zhangpengjie2@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To kwepemr200004.china.huawei.com (7.202.195.241) Just a gentle ping on this patch. Thanks, Pengjie On 2/13/2026 6:06 PM, Pengjie Zhang wrote: > The ACPI spec defines 'lowest_nonlinear_perf' as the threshold for > linear performance scaling. Performance levels below this threshold > are typically inefficient and should not be used by default. > > Currently, the QoS minimum request is initialized to 0. This defaults > the performance floor to the absolute "Lowest Performance" state > instead of "lowest_nonlinear_perf", allowing the CPU to operate in > an inefficient range unnecessarily. > > Signed-off-by: Pengjie Zhang > --- > Changes in v2: > - Renamed the patch subject to better reflect the logic change. > - Updated the commit log to clarify ACPI spec details. > Link to v1:https://lore.kernel.org/all/20260116094555.2978887-1-zhangpengjie2@huawei.com/ > --- > drivers/cpufreq/cppc_cpufreq.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c > index 7e8042efedd1..4a3031d9fcf4 100644 > --- a/drivers/cpufreq/cppc_cpufreq.c > +++ b/drivers/cpufreq/cppc_cpufreq.c > @@ -333,9 +333,23 @@ static unsigned int cppc_cpufreq_fast_switch(struct cpufreq_policy *policy, > return target_freq; > } > > -static int cppc_verify_policy(struct cpufreq_policy_data *policy) > +static int cppc_verify_policy(struct cpufreq_policy_data *policy_data) > { > - cpufreq_verify_within_cpu_limits(policy); > + if (policy_data->min == FREQ_QOS_MIN_DEFAULT_VALUE) { > + struct cpufreq_policy *policy __free(put_cpufreq_policy) = > + cpufreq_cpu_get(policy_data->cpu); > + struct cppc_cpudata *cpu_data; > + > + if (!policy) > + return -EINVAL; > + > + cpu_data = policy->driver_data; > + policy_data->min = cppc_perf_to_khz(&cpu_data->perf_caps, > + cpu_data->perf_caps.lowest_nonlinear_perf); > + } > + > + cpufreq_verify_within_cpu_limits(policy_data); > + > return 0; > } >