[alsa-devel] [PATCH 1/3] ALSA: hda - add new function snd_hda_bus_reset() for codec communitation error

[Takashi Iwai]

At Mon,  8 Apr 2013 13:53:44 -0400,
mengdong.lin at intel.com wrote:
> 
> From: Mengdong Lin <mengdong.lin at intel.com>
> 
> A new function snd_hda_bus_reset() is defined to suspend and resume all codecs
> on the hda bus.

You mixed up the result and the purpose in the description :)

The purpose of snd_hda_bus_reset() is to reset the codecs on the bus,
and eventually this is implemented as temporary suspend-and-resume
calls as an ad hoc solution.

> It will be called by bus reset ops azx_bus_reset() as a rescue
> of codec communitation error.
> 
> snd_hda_suspend & snd_hda_resume will no longer be called by azx_bus_reset.
> So snd_hda_resume will only be used in system resume and may delay resuming a
> codec.

And write why this movement is needed.


Takashi


> Signed-off-by: Mengdong Lin <mengdong.lin at intel.com>
> 
> diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
> index 17286b3..a05af8b 100644
> --- a/sound/pci/hda/hda_codec.c
> +++ b/sound/pci/hda/hda_codec.c
> @@ -5523,6 +5523,26 @@ int snd_hda_resume(struct hda_bus *bus)
>  	return 0;
>  }
>  EXPORT_SYMBOL_HDA(snd_hda_resume);
> +
> +/**
> + * snd_hda_bus_reset - reset the codecs, i.e. suspend and resume the codecs
> + * @bus: the HDA bus
> + *
> + * Returns 0 if successful.
> + */
> +int snd_hda_bus_reset(struct hda_bus *bus)
> +{
> +	struct hda_codec *codec;
> +
> +	list_for_each_entry(codec, &bus->codec_list, list) {
> +		cancel_delayed_work_sync(&codec->jackpoll_work);
> +		if (hda_codec_is_power_on(codec))
> +			hda_call_codec_suspend(codec, false);
> +		hda_call_codec_resume(codec);
> +	}
> +	return 0;
> +}
> +EXPORT_SYMBOL_HDA(snd_hda_bus_reset);
>  #endif /* CONFIG_PM */
>  
>  /*
> diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
> index c93f902..6061360 100644
> --- a/sound/pci/hda/hda_codec.h
> +++ b/sound/pci/hda/hda_codec.h
> @@ -1076,6 +1076,7 @@ void snd_hda_unlock_devices(struct hda_bus *bus);
>  #ifdef CONFIG_PM
>  int snd_hda_suspend(struct hda_bus *bus);
>  int snd_hda_resume(struct hda_bus *bus);
> +int snd_hda_bus_reset(struct hda_bus *bus);
>  #endif
>  
>  static inline
> diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> index 735567e..6f11c7a 100644
> --- a/sound/pci/hda/hda_intel.c
> +++ b/sound/pci/hda/hda_intel.c
> @@ -1659,8 +1659,7 @@ static void azx_bus_reset(struct hda_bus *bus)
>  		struct azx_pcm *p;
>  		list_for_each_entry(p, &chip->pcm_list, list)
>  			snd_pcm_suspend_all(p->pcm);
> -		snd_hda_suspend(chip->bus);
> -		snd_hda_resume(chip->bus);
> +		snd_hda_bus_reset(chip->bus);
>  	}
>  #endif
>  	bus->in_reset = 0;
> -- 
> 1.7.10.4
>