diff options
| author | Peter Wang <peter.wang@mediatek.com> | 2023-08-31 21:08:26 +0800 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2023-10-13 13:16:09 -0400 |
| commit | b50d9c27a31ed617e2e39787d134f8207d70e5af (patch) | |
| tree | e8aa416382681c9cc81a41b0dfd8e3c54bf401e0 /drivers/ufs | |
| parent | 6fd53da45bbc834b9cfdf707d2f7ebe666667943 (diff) | |
scsi: 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 (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>
Diffstat (limited to 'drivers/ufs')
| -rw-r--r-- | drivers/ufs/core/ufshcd.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 729f49cfff4c..af576d3606f6 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -1402,6 +1402,13 @@ 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; |