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

[Can Guo <cang@codeaurora.org>]

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.