[alsa-devel] [PATCH v3 01/10] ALSA: hda/hdmi - implement mst_no_extra_pcms flag

[Pierre-Louis Bossart]

On 9/10/19 1:29 PM, Kai Vehmanen wrote:
> When mst_no_extra_pcms flag is set, the codec should not
> use backup PCMs to handle DP-MST scenarios. Instead a simple
> 1:1 mapping is assumed between PCMs and converters.

mst_no_extra_pcms is not set, which makes it hard to review and get the 
picture of what this does.

> 
> Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
> ---
>   include/sound/hda_codec.h  |  1 +
>   sound/pci/hda/patch_hdmi.c | 19 ++++++++++++++-----
>   2 files changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/include/sound/hda_codec.h b/include/sound/hda_codec.h
> index 9a0393cf024c..ac18f428eda6 100644
> --- a/include/sound/hda_codec.h
> +++ b/include/sound/hda_codec.h
> @@ -254,6 +254,7 @@ struct hda_codec {
>   	unsigned int force_pin_prefix:1; /* Add location prefix */
>   	unsigned int link_down_at_suspend:1; /* link down at runtime suspend */
>   	unsigned int relaxed_resume:1;	/* don't resume forcibly for jack */
> +	unsigned int mst_no_extra_pcms:1; /* no backup PCMs for DP-MST */
>   
>   #ifdef CONFIG_PM
>   	unsigned long power_on_acct;
> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> index bca5de78e9ad..59aaee4a40fd 100644
> --- a/sound/pci/hda/patch_hdmi.c
> +++ b/sound/pci/hda/patch_hdmi.c
> @@ -2072,15 +2072,24 @@ static bool is_hdmi_pcm_attached(struct hdac_device *hdac, int pcm_idx)
>   static int generic_hdmi_build_pcms(struct hda_codec *codec)
>   {
>   	struct hdmi_spec *spec = codec->spec;
> -	int idx;
> +	int idx, pcm_num;
>   
>   	/*
>   	 * for non-mst mode, pcm number is the same as before
> -	 * for DP MST mode, pcm number is (nid number + dev_num - 1)
> -	 *  dev_num is the device entry number in a pin
> -	 *
> +	 * for DP MST mode without extra PCM, pcm number is same
> +	 * for DP MST mode with extra PCMs, pcm number is
> +	 *  (nid number + dev_num - 1)
> +	 * dev_num is the device entry number in a pin
>   	 */
> -	for (idx = 0; idx < spec->num_nids + spec->dev_num - 1; idx++) {
> +
> +	if (codec->mst_no_extra_pcms)
> +		pcm_num = spec->num_nids;
> +	else
> +		pcm_num = spec->num_nids + spec->dev_num - 1;
> +
> +	codec_dbg(codec, "hdmi: pcm_num set to %d\n", pcm_num);
> +
> +	for (idx = 0; idx < pcm_num; idx++) {
>   		struct hda_pcm *info;
>   		struct hda_pcm_stream *pstr;
>   
>