From 89434cbd2dabb56bedc633c1413bd168d7726454 Mon Sep 17 00:00:00 2001 From: Peter Wang Date: Wed, 23 Aug 2023 17:29:48 +0800 Subject: [PATCH] FROMLIST: ufs: core: fix abnormal scale up after scale down 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(requue 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; ..... Bug: 298004596 Link: https://lore.kernel.org/all/20230831130826.5592-4-peter.wang@mediatek.com/ Change-Id: I3ea77255f1b3845e9dd7bf6b050f3e9ba1f5f3f2 Signed-off-by: Peter Wang --- drivers/ufs/core/ufshcd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index a1ab4a71eab1..3ff3301f5262 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -1464,6 +1464,13 @@ static int ufshcd_devfreq_target(struct device *dev, return 0; } + /* Skip scaling clock when clock scaling is suspended */ + if (hba->clk_scaling.is_suspended) { + spin_unlock_irqrestore(hba->host->host_lock, irq_flags); + dev_warn(hba->dev, "clock scaling is suspended, skip"); + return 0; + } + if (!hba->clk_scaling.active_reqs) sched_clk_scaling_suspend_work = true;