From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout12.his.huawei.com (canpmsgout12.his.huawei.com [113.46.200.227]) (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 559681DF742; Thu, 5 Mar 2026 07:00:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.227 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772694043; cv=none; b=MiUAxpXtd1VflIVHESYxdsYN+iiYOaC2CAIAoen9EfZbiNPybXQCbbs0K/1NhMG3qj9Agvqp06OFWoq/tCMy9mdYb+5T9ThJS3WTqWfqA8+Xo3AISDuONHOZryX7T0RfHNlEOeS6JLK7FyIp84UzVOZTbh6EVQFuQsK1z6iMQwc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772694043; c=relaxed/simple; bh=xl0zACBZtanATNvK45qwZ+mHQ2zZocrgb1ymP4/IDp8=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=l/HjemL4UBMW93o8ep0UJXV1RN+u2P4C9LlTQSiCB/wui1n5jeEX44yPHPHjIMGayY8RXm4hPwucxBJtkIMKnIIaYHt1k7YQQfHMJ2XoWRVSBYIMWyeYwtRRbIf5a3yJsHtqeioa5RiFdjIm4xTZPGFn1kjDiuivY0ZvGonNAlw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=hisilicon.com; spf=pass smtp.mailfrom=hisilicon.com; arc=none smtp.client-ip=113.46.200.227 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=hisilicon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hisilicon.com Received: from mail.maildlp.com (unknown [172.19.163.200]) by canpmsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4fRL0c0tR8znTVx; Thu, 5 Mar 2026 14:56:00 +0800 (CST) Received: from kwepemf200017.china.huawei.com (unknown [7.202.181.10]) by mail.maildlp.com (Postfix) with ESMTPS id 408CF40567; Thu, 5 Mar 2026 15:00:36 +0800 (CST) Received: from [10.67.121.58] (10.67.121.58) by kwepemf200017.china.huawei.com (7.202.181.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 5 Mar 2026 15:00:35 +0800 Message-ID: <8af0818e-7f98-4bb0-96b9-d34368e9b58f@hisilicon.com> Date: Thu, 5 Mar 2026 15:00:35 +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: Viresh Kumar , "zhangpengjie (A)" , Sumit Gupta , Pierre Gondois , Prashant Malani , Ionela Voinescu , CC: , , , , , , , , , References: <20260213100633.15413-1-zhangpengjie2@huawei.com> <54f5795f-2c0b-49f2-a319-216c17657c0f@huawei.com> Content-Language: en-US From: Jie Zhan In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To kwepemf200017.china.huawei.com (7.202.181.10) Hi Viresh, I'm happy with rewiewing or maintaining this. We're consistently using the CPPC cpufreq driver for our SoCs. BTW, will take a look at Pengjie's patches soon! Thanks, Jie On 3/5/2026 2:32 PM, Viresh Kumar wrote: > Added few more people > > I think we should updated MAINTAINERS with a list of reviewers or maintainers > for the CPPC driver. Who all want to be part of the reviewers list ? > > On 03-03-26, 20:03, zhangpengjie (A) wrote: >> 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; >>> } >