On 2019-11-15 15:18, Stanley Chu wrote:
Hi Can,
On Fri, 2019-11-15 at 15:03 +0800, Can Guo wrote:
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 for explanation.
I fully understand the intention of this patch.
Just wonder if "if (!pm_runtime_suspended(hba->dev))" could be removed
and then always do pm_runtime_get_sync() here.
This could avoid possible racing and enable AH8 regardless of current
runtime status.
Thanks,
Can Guo.
Thanks,
Stanley
Hi Stanley,
Actually, I thought about the way you reommand.
But I guess the author's intention here is to update the AH8 timer
only when current runtime status is RPM_ACTIVE. If it is not RPM_ACTIVE,
we just update the hba->ahit and bail out, because the AH8 timer will be
updated in ufshcd_reusme() eventually when hba is resumed. This can
avoid
frequently waking up hba just for accessing a single register.
How do you think?
Thanks,
Can Guo.
