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

[Vitaly Chikunov <vt@altlinux.org>]

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@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?

Thanks,

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