[alsa-devel] [RFC PATCH v2 4/6] ALSA: hda/hdmi - implement mst_no_extra_pcms flag

[Pierre-Louis Bossart]

On 9/6/19 9:29 AM, Kai Vehmanen wrote:
> When mst_no_exxtra_pcms flag is set, the codec should not

typo: extra

> use backup PCMs to handle DP-MST scenarios. Instead a simple
> 1:1 mapping is assumed between PCMs and converters.
> 
> Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
> ---
>   sound/pci/hda/patch_hdmi.c | 19 ++++++++++++++-----
>   1 file changed, 14 insertions(+), 5 deletions(-)
> 
> 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;
>   
>