Re: [PATCH v3 3/4] ALSA: hda - display audio call ncts callback

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 10 Aug 2015, libin.yang@intel.com wrote:
> From: Libin Yang <libin.yang@intel.com>
>
> On some Intel platforms, display audio need set N/CTS
> manually at some TMDS frequencies.
>
> Signed-off-by: Libin Yang <libin.yang@intel.com>
> ---
>  sound/pci/hda/patch_hdmi.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> index a97db5f..918435e 100644
> --- a/sound/pci/hda/patch_hdmi.c
> +++ b/sound/pci/hda/patch_hdmi.c
> @@ -1770,6 +1770,16 @@ static bool check_non_pcm_per_cvt(struct hda_codec *codec, hda_nid_t cvt_nid)
>  	return non_pcm;
>  }
>  
> +/* There is a fixed mapping between audio pin node and display port
> + * on current Intel platforms:
> + * Pin Widget 5 - PORT B (port = 1 in i915 driver)
> + * Pin Widget 6 - PORT C (port = 2 in i915 driver)
> + * Pin Widget 7 - PORT D (port = 3 in i915 driver)
> + */
> +static int intel_pin2port(hda_nid_t pin_nid)
> +{
> +	return pin_nid - 4;
> +}
>  
>  /*
>   * HDMI callbacks
> @@ -1786,6 +1796,8 @@ static int generic_hdmi_playback_pcm_prepare(struct hda_pcm_stream *hinfo,
>  	int pin_idx = hinfo_to_pin_index(codec, hinfo);
>  	struct hdmi_spec_per_pin *per_pin = get_pin(spec, pin_idx);
>  	hda_nid_t pin_nid = per_pin->pin_nid;
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +	struct i915_audio_component *acomp = codec->bus->core.audio_component;
>  	bool non_pcm;
>  	int pinctl;
>  
> @@ -1802,6 +1814,17 @@ static int generic_hdmi_playback_pcm_prepare(struct hda_pcm_stream *hinfo,
>  		intel_not_share_assigned_cvt(codec, pin_nid, per_pin->mux_idx);
>  	}
>  
> +	/* Set N/CTS for HSW, BDW and SKL platforms.
> +	 * These platforms need call set_ncts to set the N/CTS manually,
> +	 * otherwise there is no sound in some sample rates.
> +	 */
> +	if (is_haswell_plus(codec)) {

Maybe you should move this check to the graphics side, and do the call
whenever the callback is non-NULL, and you can be sure of the pin->port
mapping?

> +		/* Todo: add DP1.2 MST audio support later */
> +		if (acomp && acomp->ops && acomp->ops->set_ncts)
> +			acomp->ops->set_ncts(acomp->dev,
> +				intel_pin2port(pin_nid),
> +				0, runtime->rate);
> +	}
>  	non_pcm = check_non_pcm_per_cvt(codec, cvt_nid);
>  	mutex_lock(&per_pin->lock);
>  	per_pin->channels = substream->runtime->channels;
> -- 
> 1.9.1
>
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-- 
Jani Nikula, Intel Open Source Technology Center
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