From nobody Mon Nov 25 22:35:14 2024 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) (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 DCB393D69; Thu, 24 Oct 2024 02:16:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.191 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729736176; cv=none; b=O27Og3xt9VxC39zhKVgTQFprpuq42d1Jz9rxA5uYmv0HMFkJsrJzxBFIowT2GvS8J9kGxRLJ8Q9zhQwjapOlPH+9K5dNtrz74re77LsvI/rcCvsoBeuYkpf38Pit82WA6orBQHW7/lGwEGbSrHnhodUPiGbcw9EfU+MEfKUWu6E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729736176; c=relaxed/simple; bh=p+G2AcOoCkBvlUjYy6aT15l0q4IcI/xUhywccyK9ZxM=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=SQelx2uie3UU8+qJ9j2NMZyNn9Og65m8IxNSVKpcV5eOWWaOYocWuCqRawJPyhgHKDgtczNhx0SmjHxccCl3TO/7Xp1LqG7i8Kl4bRndQCygblcW1jqXShOOEEBfHi/8gpxzyZaJQaYkviX6V2uJgED7VBuOktJkYB+NkCG8dX4= 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=45.249.212.191 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 [172.19.163.17]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4XYqHV1W53z1jvqb; Thu, 24 Oct 2024 10:14:46 +0800 (CST) Received: from kwepemj200003.china.huawei.com (unknown [7.202.194.15]) by mail.maildlp.com (Postfix) with ESMTPS id 06D401A0188; Thu, 24 Oct 2024 10:16:10 +0800 (CST) Received: from huawei.com (10.175.103.91) by kwepemj200003.china.huawei.com (7.202.194.15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 24 Oct 2024 10:16:09 +0800 From: liwei To: , , , , , CC: , , , Subject: [PATCH v3] cpufreq/cppc: fix perf_to_khz/khz_to_perf conversion exception Date: Thu, 24 Oct 2024 10:29:52 +0800 Message-ID: <20241024022952.2627694-1-liwei728@huawei.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemj200003.china.huawei.com (7.202.194.15) Content-Type: text/plain; charset="utf-8" When the nominal_freq recorded by the kernel is equal to the lowest_freq, and the frequency adjustment operation is triggered externally, there is a logic error in cppc_perf_to_khz()/cppc_khz_to_perf(), resulting in perf and khz conversion errors. 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 Acked-by: Viresh Kumar --- v2: - Fix similar issue in cppc_khz_to_perf() --- v3: - Add acked-by tag --- drivers/acpi/cppc_acpi.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index b73b3aa92f3f..c3fc2c05d868 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1916,9 +1916,15 @@ unsigned int cppc_perf_to_khz(struct cppc_perf_caps = *caps, unsigned int perf) u64 mul, div; =20 if (caps->lowest_freq && caps->nominal_freq) { - mul =3D caps->nominal_freq - caps->lowest_freq; + /* Avoid special case when nominal_freq is equal to lowest_freq */ + if (caps->lowest_freq =3D=3D caps->nominal_freq) { + mul =3D caps->nominal_freq; + div =3D caps->nominal_perf; + } else { + mul =3D caps->nominal_freq - caps->lowest_freq; + div =3D caps->nominal_perf - caps->lowest_perf; + } mul *=3D KHZ_PER_MHZ; - div =3D caps->nominal_perf - caps->lowest_perf; offset =3D caps->nominal_freq * KHZ_PER_MHZ - div64_u64(caps->nominal_perf * mul, div); } else { @@ -1939,11 +1945,17 @@ unsigned int cppc_khz_to_perf(struct cppc_perf_caps= *caps, unsigned int freq) { s64 retval, offset =3D 0; static u64 max_khz; - u64 mul, div; + u64 mul, div; =20 if (caps->lowest_freq && caps->nominal_freq) { - mul =3D caps->nominal_perf - caps->lowest_perf; - div =3D caps->nominal_freq - caps->lowest_freq; + /* Avoid special case when nominal_freq is equal to lowest_freq */ + if (caps->lowest_freq =3D=3D caps->nominal_freq) { + mul =3D caps->nominal_perf; + div =3D caps->nominal_freq; + } else { + mul =3D caps->nominal_perf - caps->lowest_perf; + div =3D caps->nominal_freq - caps->lowest_freq; + } /* * We don't need to convert to kHz for computing offset and can * directly use nominal_freq and lowest_freq as the div64_u64 --=20 2.25.1