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b50d9c27a3
When no active_reqs, devfreq_monitor (thread A) will suspend clock scaling. But it may have racing with clk_scaling.suspend_work (thread B) and actually not suspend clock scaling (requeue after suspend). Next time after polling_ms, devfreq_monitor read clk_scaling.window_start_t = 0 then scale up clock abnormal. Below is racing step: devfreq->work (Thread A) devfreq_monitor update_devfreq ..... ufshcd_devfreq_target queue_work(hba->clk_scaling.workq, 1 &hba->clk_scaling.suspend_work) ..... 5 queue_delayed_work(devfreq_wq, &devfreq->work, msecs_to_jiffies(devfreq->profile->polling_ms)); 2 hba->clk_scaling.suspend_work (Thread B) ufshcd_clk_scaling_suspend_work __ufshcd_suspend_clkscaling devfreq_suspend_device(hba->devfreq); 3 cancel_delayed_work_sync(&devfreq->work); 4 hba->clk_scaling.window_start_t = 0; ..... Signed-off-by: Peter Wang <peter.wang@mediatek.com> Link: https://lore.kernel.org/r/20230831130826.5592-4-peter.wang@mediatek.com Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>