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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Thara Gopinath <thara.gopinath@linaro.org>
Cc: agross@kernel.org, bjorn.andersson@linaro.org,
	rui.zhang@intel.com, daniel.lezcano@linaro.org,
	rjw@rjwysocki.net, robh+dt@kernel.org, tdas@codeaurora.org,
	mka@chromium.org, linux-arm-msm@vger.kernel.org,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [Patch v3 3/6] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
Date: Fri, 9 Jul 2021 12:16:46 +0530	[thread overview]
Message-ID: <20210709064646.7vjgiba2o7beudly@vireshk-i7> (raw)
In-Reply-To: <20210708120656.663851-4-thara.gopinath@linaro.org>

On 08-07-21, 08:06, Thara Gopinath wrote:
>  static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>  {
>  	struct platform_device *pdev = cpufreq_get_driver_data();
> @@ -370,6 +480,10 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>  			dev_warn(cpu_dev, "failed to enable boost: %d\n", ret);
>  	}
>  
> +	ret = qcom_cpufreq_hw_lmh_init(policy, index);

You missed unregistering EM here (which is also missing from exit,
which you need to fix first in a separate patch).

> +	if (ret)
> +		goto error;
> +
>  	return 0;
>  error:
>  	kfree(data);
> @@ -389,6 +503,10 @@ static int qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
>  
>  	dev_pm_opp_remove_all_dynamic(cpu_dev);
>  	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
> +	if (data->lmh_dcvs_irq > 0) {
> +		devm_free_irq(cpu_dev, data->lmh_dcvs_irq, data);

Why using devm variants here and while requesting the irq ? 

> +		cancel_delayed_work_sync(&data->lmh_dcvs_poll_work);
> +	}

Please move this to qcom_cpufreq_hw_lmh_exit() or something.

Now with sequence of disabling interrupt, etc, I see a potential
problem.

CPU0                                    CPU1

qcom_cpufreq_hw_cpu_exit()
-> devm_free_irq();
                                        qcom_lmh_dcvs_poll()
                                        -> qcom_lmh_dcvs_notify()
                                          -> enable_irq()

-> cancel_delayed_work_sync();


What will happen if enable_irq() gets called after freeing the irq ?
Not sure, but it looks like you will hit this then from manage.c:

WARN(!desc->irq_data.chip, KERN_ERR "enable_irq before
                                     setup/request_irq: irq %u\n", irq))

?

You got a chicken n egg problem :)

-- 
viresh

  parent reply	other threads:[~2021-07-09  6:46 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-08 12:06 [Patch v3 0/6] Introduce LMh driver for Qualcomm SoCs Thara Gopinath
2021-07-08 12:06 ` [Patch v3 1/6] firmware: qcom_scm: Introduce SCM calls to access LMh Thara Gopinath
2021-07-10  4:02   ` Bjorn Andersson
2021-07-08 12:06 ` [Patch v3 2/6] thermal: qcom: Add support for LMh driver Thara Gopinath
2021-07-10  4:15   ` Bjorn Andersson
2021-07-13  0:49     ` Thara Gopinath
2021-07-08 12:06 ` [Patch v3 3/6] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support Thara Gopinath
2021-07-08 20:00   ` kernel test robot
2021-07-09  6:46   ` Viresh Kumar [this message]
2021-07-09 15:37     ` Thara Gopinath
2021-07-12  4:35       ` Viresh Kumar
2021-07-12  4:41       ` Viresh Kumar
2021-07-13  1:18         ` Thara Gopinath
2021-07-13  3:18           ` Viresh Kumar
2021-07-14 12:37             ` Thara Gopinath
2021-07-10  4:57   ` Bjorn Andersson
2021-07-13  1:09     ` Thara Gopinath
2021-07-08 12:06 ` [Patch v3 4/6] arm64: boot: dts: qcom: sdm45: Add support for LMh node Thara Gopinath
2021-07-10  4:17   ` Bjorn Andersson
2021-07-19 16:33   ` Bjorn Andersson
2021-07-19 22:44     ` Thara Gopinath
2021-07-08 12:06 ` [Patch v3 5/6] arm64: boot: dts: qcom: sdm845: Remove cpufreq cooling devices for CPU thermal zones Thara Gopinath
2021-07-10  4:17   ` Bjorn Andersson
2021-07-08 12:06 ` [Patch v3 6/6] dt-bindings: thermal: Add dt binding for QCOM LMh Thara Gopinath
2021-07-10  4:21   ` Bjorn Andersson
2021-07-13  0:54     ` Thara Gopinath
2021-07-12 17:32   ` Rob Herring
2021-07-22  3:14 ` [Patch v3 0/6] Introduce LMh driver for Qualcomm SoCs Steev Klimaszewski
2021-07-27 15:29   ` Thara Gopinath
2021-07-27 17:43     ` Steev Klimaszewski

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