HDMI driver format channel mismatch bug

[sujith kumar reddy]

Hi Alsa Team,

Sound is not coming in sony tv . which has below supported formats and
channels.

please find the attached  edid information and hw_params dump.

with intel platform, same monitor populating 2 channels as max in hw_params
in dump.
but with AMD card, its populating as 6 channels.


When we digged the code, we found that snd_hdmi_eld_update_pcm_info   API
setting hinfo->channel_max as 8 and as channels max retrieved from sad info
as 6.


for LPCM , why the channel max assignment logic is not safeguared with
audio format check as LPCM ?


snippet code:

/* update PCM info based on ELD */void
snd_hdmi_eld_update_pcm_info(struct parsed_hdmi_eld *e,
			      struct hda_pcm_stream *hinfo){
	u32 rates;
	u64 formats;
	unsigned int maxbps;
	unsigned int channels_max;
	int i;

	/* assume basic audio support (the basic audio flag is not in ELD;	 *
however, all audio capable sinks are required to support basic	 *
audio) */
	rates = SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 |
		SNDRV_PCM_RATE_48000;
	formats = SNDRV_PCM_FMTBIT_S16_LE;
	maxbps = 16;
	channels_max = 2;
	for (i = 0; i < e->sad_count; i++) {
		struct cea_sad *a = &e->sad[i];
		rates |= a->rates;
		if (a->channels > channels_max)
			channels_max = a->channels;
		if (a->format == AUDIO_CODING_TYPE_LPCM) {
			if (a->sample_bits & AC_SUPPCM_BITS_20) {
				formats |= SNDRV_PCM_FMTBIT_S32_LE;
				if (maxbps < 20)
					maxbps = 20;
			}
			if (a->sample_bits & AC_SUPPCM_BITS_24) {
				formats |= SNDRV_PCM_FMTBIT_S32_LE;
				if (maxbps < 24)
					maxbps = 24;
			}
		}
	}

	/* restrict the parameters by the values the codec provides */
	hinfo->rates &= rates;
	hinfo->formats &= formats;
	hinfo->maxbps = min(hinfo->maxbps, maxbps);
	hinfo->channels_max = min(hinfo->channels_max, channels_max);

>>>>>>>>>>the above statement channels_max is the maximum of channels supported of different formats.

For example: the below attached edid is of sony tv. which supports two
formats(LPCM and AC3)

            LPCM --->supports 2 channels

            AC3 ----->Supports 6 channels you can see in the attached edid info.

       As AMD supports LPCM ...>when we keep logs here we got
channels_max =6 .in which sound is not observed on tv .when we
hardcode to 2 channels

       the sound is heard from monitor. As you see the above code
..for loop is not distinguishing channels_max for different formats.

}


Thanks in Advance



https://pastebin.com/t41DqErH   ------edid information
https://pastebin.com/4m56h10R  -----dump hw-params

Thanks
Sujith