From patchwork Tue Apr 30 10:12:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: liwei X-Patchwork-Id: 794167 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) (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 A6262127E01; Tue, 30 Apr 2024 10:13:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.35 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714472021; cv=none; b=McUlw6Y/1whAn+7hvd7dpH5sXJQVPeBnoH7+qT4WeT5L95BstHRHfwuaCG1oCPoI/LviU+sqgQgDEgF49g1cvzoamR6NzlGbonSsbelcDNZnWFytPnGNnz/7TO+bnggphOWIN2CsiX/QMS/vs178E4yLFTzNxrxZL/KjR9ERN80= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714472021; c=relaxed/simple; bh=2lCXfA+umKRhdNnXAPu6RvMFY/5jIpKpRctq6cIERzw=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=VAxng+Jbvi4danpfNP/O5gkC0fN0Tk59mNKBkS+jcpfK+yVwamj6qEBGeHUC/vwiEuD5h7SEdsP+AcqzJPZojSJSHGBHvbPjQ4ok7yw/s1tqBxW0xbyx3spnmEeX6E3AEScRZRYDLoIlNX79muClH+xcVdH6z3sCRUXfhdcto8Y= 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; arc=none smtp.client-ip=45.249.212.35 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 Received: from mail.maildlp.com (unknown [172.19.88.214]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4VTGD3169Zz1RDTL; Tue, 30 Apr 2024 18:10:27 +0800 (CST) Received: from dggpemm500018.china.huawei.com (unknown [7.185.36.111]) by mail.maildlp.com (Postfix) with ESMTPS id 068701A016C; Tue, 30 Apr 2024 18:13:37 +0800 (CST) Received: from huawei.com (10.175.103.91) by dggpemm500018.china.huawei.com (7.185.36.111) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Tue, 30 Apr 2024 18:13:36 +0800 From: liwei To: , , , CC: , , , Subject: [PATCH] cpufreq/cppc: fix perf_to_khz conversion exception Date: Tue, 30 Apr 2024 18:12:27 +0800 Message-ID: <20240430101227.2133288-1-liwei728@huawei.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500018.china.huawei.com (7.185.36.111) When the nominal_freq recorded by the kernel is equal to lowest_freq and the frequency reduction operation is triggered externally, there is a conversion logic error in cppc_perf_to_khz(), causing the kernel to be unable to feedback the true frequency. Fix this by adding the branch processing logic when nominal_freq is equal to lowest_freq. Fixes: ec1c7ad47664 ("cpufreq: CPPC: Fix performance/frequency conversion") Signed-off-by: liwei --- drivers/acpi/cppc_acpi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index a40b6f3946ef..92aac6974e0e 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1869,9 +1869,15 @@ unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf) u64 mul, div; if (caps->lowest_freq && caps->nominal_freq) { - mul = caps->nominal_freq - caps->lowest_freq; + /* Avoid the special case when nominal_freq is equal to lowest_freq */ + if (caps->lowest_freq == caps->nominal_freq) { + mul = caps->nominal_freq; + div = caps->nominal_perf; + } else { + mul = caps->nominal_freq - caps->lowest_freq; + div = caps->nominal_perf - caps->lowest_perf; + } mul *= KHZ_PER_MHZ; - div = caps->nominal_perf - caps->lowest_perf; offset = caps->nominal_freq * KHZ_PER_MHZ - div64_u64(caps->nominal_perf * mul, div); } else {