Re: [Patch v3 3/6] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2021-07-13 03:18:55
Also in:
linux-arm-msm, linux-pm, lkml
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2021-07-13 03:18:55
Also in:
linux-arm-msm, linux-pm, lkml
On 12-07-21, 21:18, Thara Gopinath wrote:
So I really need the interrupt to fire and then the timer to kick in and take up the monitoring. I can think of introducing a variable is_disabled which is updated and read under a spinlock. qcom_cpufreq_hw_cpu_exit can hold the spinlock and set is_disabled to true prior to cancelling the work queue or disabling the interrupt. Before re-enabling the interrupt or re-queuing the work in qcom_lmh_dcvs_notify, is_disabled can be read and checked.
Or you can make the lmh_dcvs_poll_work item a pointer and mark it NULL in exit, with proper locking etc.
But does this problem not exist in target_index , fast_switch etc also ? One cpu can be disabling and the other one can be updating the target right?
The race doesn't happen there as cpufreq_unregister_driver() takes care of stopping everything before removing the policy. To be more precise, governor's ->stop() function is responsible for making sure that frequency won't be updated any further. -- viresh