Re: [PATCH v5 3/7] scsi: ufs: Fix up auto hibern8 enablement

Can Guo
2019-11-15T07:03:41Z

On 2019-11-15 14:35, Stanley Chu wrote:
> Hi Can,
>
> On Thu, 2019-11-14 at 22:09 -0800, Can Guo wrote:
>> + if (hba->ahit != ahit)
>> + hba->ahit = ahit;
>> spin_unlock_irqrestore(hba->host->host_lock, flags);
>> + if (!pm_runtime_suspended(hba->dev)) {
>
> Always do pm_runtime_get_sync() here could avoid possible racing?
>
> And thus AH8 could be enabled regardless of runtime status.
>
>> + pm_runtime_get_sync(hba->dev);
>> + ufshcd_hold(hba, false);
>> + ufshcd_auto_hibern8_enable(hba);
>> + ufshcd_release(hba);
>> + pm_runtime_put(hba->dev);
>> + }
>> }
>
> Thanks,
> Stanley

Hi Stanley,

if !pm_runtime_suspended() is true, hba->dev's runtime status, other
than RPM_ACTIVE,
may be RPM_SUSPENDING or RPM_RESUMING. So, here for safty, do
pm_runtime_get_sync() once
before access registers, in case we hit corner cases in which powers
and/or clocks are OFF.

Thanks,
Can Guo.