From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1B78E2BD58C; Thu, 31 Jul 2025 08:19:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753949984; cv=none; b=Wu2Xs7r0PfJSJn+/DfqoZ8paP3WEFAKE7FyLqVjyMQnK0n4JDB4ocNv9v5F8StQZe8d1H3DR/1iw+YYY3G2vIBLpo+O5y7HuS0B9sGkFt6qzsxAXSiTFUJTQNMAHVCQ6St9VmwsR5fVzphFVrwDve7y8y15uz6le+PMvcMlVdK8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753949984; c=relaxed/simple; bh=oj3P/19FQm3GhzmA7W5xkOFOXCD4j5EfAU62nU5kIRo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JFBHjCWAmhhS5UjQ43uXn4KQWAF/eduMoctX3bFTuvmdkJYvrdTT/H2/hDLn99a6ruftAbV0ieD97tVsSn2RoKHp0TEz7iRMwhbRpogg0xGIAz2VUcpAQPalmN81QR8R4dQm1FhlmXSkeycYgwuebkDSEvYFtbzeB876ijk9XS4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 145231D13; Thu, 31 Jul 2025 01:19:33 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5A4B63F673; Thu, 31 Jul 2025 01:19:38 -0700 (PDT) Date: Thu, 31 Jul 2025 10:19:15 +0200 From: Beata Michalska To: Bowen Yu Cc: rafael@kernel.org, viresh.kumar@linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linuxarm@huawei.com, jonathan.cameron@huawei.com, zhanjie9@hisilicon.com, lihuisong@huawei.com, zhenglifeng1@huawei.com Subject: Re: [PATCH 2/2] cpufreq: CPPC: Fix error handling in cppc_scale_freq_workfn() Message-ID: References: <20250730032312.167062-1-yubowen8@huawei.com> <20250730032312.167062-3-yubowen8@huawei.com> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250730032312.167062-3-yubowen8@huawei.com> Hi Bowen, Jie On Wed, Jul 30, 2025 at 11:23:12AM +0800, Bowen Yu wrote: > From: Jie Zhan > > Perf counters could be 0 if the cpu is in a low-power idle state. Just try > it again next time and update the frequency scale when the cpu is active > and perf counters successfully return. > > Also, remove the FIE source on an actual failure. > > Signed-off-by: Jie Zhan > --- > drivers/cpufreq/cppc_cpufreq.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c > index 904006027df2..e95844d3d366 100644 > --- a/drivers/cpufreq/cppc_cpufreq.c > +++ b/drivers/cpufreq/cppc_cpufreq.c > @@ -78,12 +78,23 @@ static void cppc_scale_freq_workfn(struct kthread_work *work) > struct cppc_cpudata *cpu_data; > unsigned long local_freq_scale; > u64 perf; > + int ret; > > cppc_fi = container_of(work, struct cppc_freq_invariance, work); > cpu_data = cppc_fi->cpu_data; > > - if (cppc_get_perf_ctrs(cppc_fi->cpu, &fb_ctrs)) { > + ret = cppc_get_perf_ctrs(cppc_fi->cpu, &fb_ctrs); > + /* > + * Perf counters could be 0 if the cpu is in a low-power idle state. > + * Just try it again next time. > + */ > + if (ret == -EFAULT) > + return; Which counters are we actually talking about here ? > + > + if (ret) { > pr_warn("%s: failed to read perf counters\n", __func__); > + topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, > + cpu_data->shared_cpu_map); > return; > } And the real error here would be ... ? That makes me wonder why this has been registered as the source of the freq scale in the first place if we are to hit some serious issue. Would you be able to give an example of any? --- BR Beata > > -- > 2.33.0 > >