[d-kernel] [PATCH 1/1] dw-hdmi: add flag SNDRV_PCM_INFO_BATCH for audio via hdmi on Baikal-M

[Daniil Gnusarev]

On 04.09.2025 03:50, Vitaly Chikunov wrote:
> Daniil,
> 
> On Wed, Sep 03, 2025 at 06:41:51PM +0400, Daniil Gnusarev wrote:
>> There is an unstable sound output via HDMI with the dw-hdmi-ahb-audiо
>> driver when working on Baikal-M. Additional setting of
>> the SNDRV_PCM_INFO_BATCH flag solves this problem. Let's use it.
>>
>> Signed-off-by: Daniil Gnusarev <gnusarevda на basealt.ru>
>> ---
>>   drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c | 2 ++
>>   drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h     | 1 +
>>   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c           | 3 ++-
>>   3 files changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
>> index 89af1b6a2ef2b..af0295d3bdfcb 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
>> @@ -356,6 +356,8 @@ static int dw_hdmi_open(struct snd_pcm_substream *substream)
>>   	int ret;
>>   
>>   	runtime->hw = dw_hdmi_hw;
>> +	if (dw->data.batch_mode)
>> +		runtime->hw.info |= SNDRV_PCM_INFO_BATCH;
>>   
>>   	eld = dw->data.get_eld(dw->data.hdmi);
>>   	if (eld) {
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
>> index 3250588d39ff0..aa9f470fcd03a 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
>> @@ -11,6 +11,7 @@ struct dw_hdmi_audio_data {
>>   	struct dw_hdmi *hdmi;
>>   	u8 *(*get_eld)(struct dw_hdmi *hdmi);
>>   	unsigned regshift;
>> +	bool batch_mode;
>>   };
>>   
>>   struct dw_hdmi_i2s_audio_data {
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> index 2805b58619a76..7dc010524c0cc 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -3527,7 +3527,8 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
>>   			audio.regshift = 2;
>>   			dev_info(dev, "setting audio.regshift=%d for BE-M1000 SoC\n",
>>   				 audio.regshift);
>> -		}
>> +			audio.batch_mode = true;
>> +		} else audio.batch_mode = false;
> 
> Пожалуйста, на будущее, форматируйте код по стандартам ядра.
> 
> Кроме того, ниже в ветках кода
> 
>   "} else if (iores && config3 & HDMI_CONFIG3_GPAUD) {" и
>   "} else if (config0 & HDMI_CONFIG0_I2S) {"
> 
> вы не инициализируете audio.batch_mode, - не создает ли это проблем с
> непроинициализированной памятью?
> 

Участвуют только два драйвера, dw-hdmi-ahb-audio и dw-hdmi-gp-audio. 
Дополнительное поле создается для первого, второму не мешает, насколько 
я вижу.

> Thanks,
> 
>>   		hdmi->enable_audio = dw_hdmi_ahb_audio_enable;
>>   		hdmi->disable_audio = dw_hdmi_ahb_audio_disable;
>>   
>> -- 
>> 2.42.2
>>
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