Re: [PATCH 1/5] ASoC: rt5682-sdw: fix for JD event handling in ClockStop Mode0

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 7/3/23 15:31, Mukunda,Vijendar wrote:
> On 03/07/23 18:30, Shuming [范書銘] wrote:
>>>>>> During ClockStop Mode0, peripheral interrupts are disabled.
>>>>> I can see that the interrupts are disabled in
>>>>> rt5682_dev_system_suspend(), which is NOT a mode where the clock stop
>>>>> is used... I don't think this commit message is correct.
>>>>>
>>>>> The IMPL_DEF interrupt which is used for jack detection is not
>>>>> disabled at all during any clock stop mode, and it shouldn't
>>>>> otherwise that would break the jack detection.
>>>> You are right. The commit message is wrong and not clear.
>>>> The situation is that the manager driver uses the clock stop mode0 to do
>>> system suspension.
>>>
>>> No it does not. The clock stop is ONLY used for pm_runtime, never for system
>>> suspend. We cannot go to system suspend with the link in clock-stop mode,
>>> that will create lots of issues, that's why we perform a full pm_runtime resume
>>> in the .prepare stage.
>> OK, I got your point. Thanks. However, this issue reported by AMD. 
>> The AMD platform validated system level pm and runtime pm ops with the different modes.
>>
>> Hi Vijendar,
>> Do you have any comments?
> On AMD platforms, we are supporting two power modes.
> 1) Bus reset mode
> 2) Clock Stop Mode
> 
> In Bus reset mode, bus will re-enumerate the peripheral devices
> whereas in ClockStop Mode, applying ClockStop Mode0
> in both pm ops (runtime pm ops and system level pm ops).
> 
> Currently, SDCA interrupts are disabled on peripheral side, when system level
> suspend is invoked.
> For ClockStop mode SDW manager is not receiving any jack alert when
> SoundWire manager device is in D3 state.

That was precisely the point of clock stop mode: a peripheral can
restart the system even when it's in lower-power mode.

If there's no means to let a peripheral restart, the only benefit is
maybe to skip the enumeration time. That's not what the spec intended....

> Our expectation is when ClockStop Mode is selected, Only ClockStopMode0
> should be applied for system level suspend as well.
> We are not expecting bus reset.
> 
> We have validated these changes on our platform with Clock stop mode.
> It's working fine.
> 
>>>> The SdW device will not be re-attached when the system resume.
>>> it will re-attach, and in addition it will lose context because the manager
>>> performs a complete reset of the bus.
>>>
>>> So what's needed is to enable the interrupt, no matter what happened in the
>>> suspend transition.
>>>
>>>
>>> ------Please consider the environment before printing this e-mail.
>