[alsa-devel] [PATCH V2] ASoC: fix hdmi codec driver contest in S3

[Yang, Libin]

Hi Takashi,

>-----Original Message-----
>From: Takashi Iwai [mailto:tiwai at suse.de]
>Sent: Tuesday, March 26, 2019 7:19 PM
>To: Yang, Libin <libin.yang at intel.com>
>Cc: alsa-devel at alsa-project.org; broonie at kernel.org
>Subject: Re: [alsa-devel] [PATCH V2] ASoC: fix hdmi codec driver contest in S3
>
>On Tue, 26 Mar 2019 12:15:06 +0100,
>Yang, Libin wrote:
>>
>> Hi Takashi,
>>
>> >-----Original Message-----
>> >From: Takashi Iwai [mailto:tiwai at suse.de]
>> >Sent: Tuesday, March 26, 2019 4:54 PM
>> >To: Yang, Libin <libin.yang at intel.com>
>> >Cc: alsa-devel at alsa-project.org; broonie at kernel.org
>> >Subject: Re: [alsa-devel] [PATCH V2] ASoC: fix hdmi codec driver
>> >contest in S3
>> >
>> >On Tue, 26 Mar 2019 09:46:31 +0100,
>> >Yang, Libin wrote:
>> >>
>> >> Hi Takashi
>> >>
>> >> >
>> >> >In the case of legacy HD-audio, we "fixed" the problem by avoiding
>> >> >the trigger of async work at resume, but let it be triggered from
>> >> >runtime resume.  In ASoC case, however, it's no option.
>> >> >
>> >> >Maybe a possible solution in the sound driver side would be to
>> >> >move from system suspend/resume to ASoC component
>suspend/resume.
>> >> >The runtime suspend/resume can be kept as is, and call
>> >> >pm_runtime_force_suspend and resume from the component
>> >suspend/resume
>> >> >callbacks.  Since the component callbacks are certainly processed
>> >> >before DAPM events, this should assure the order.
>> >>
>> >> I tried to move display power setting from runtime suspend/resume
>> >> to component suspend/resume. I found there may be another issue:
>> >> playback will NOT call component suspend/resume.
>> >> This  means we will never have chance to set the display power if
>> >> we don't do the S3.
>> >
>> >The runtime suspend/resume are fine and need to be kept, I suppose.
>> >The only problem is the system suspend/resume callbacks that call
>> >pm_runtime_force_*().  Just moving these two to component would work?
>> >
>>
>> Let's see the flow of the suspend:
>> 1. Component suspend is called. It will call snd_hdac_display_power()
>> to turn off the display power.
>
>No, what I meant was to make the component suspend calling
>pm_runtime_force_suspend() instead of the system suspend.
>Ditto for the component resume calling pm_runtime_force_resume().

Aha, I get your idea now. I will have a try tomorrow as I don't have
the device on hand now.

Regards,
Libin

>
>
>Takashi