linux-kernel - Re: [PATCH 1/2] ALSA: hda/realtek: Accelerate the front MIC charging and discharging of the 897 codec

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Message-ID: <87jz3j1ug9.wl-tiwai@suse.de>
Date: Mon, 04 Aug 2025 08:17:58 +0200
From: Takashi Iwai <tiwai@...e.de>
To: wangdich9700@....com
Cc: lgirdwood@...il.com,
	broonie@...nel.org,
	perex@...ex.cz,
	tiwai@...e.com,
	linux-kernel@...r.kernel.org,
	alsa-devel@...a-project.org,
	linux-arm-kernel@...ts.infradead.org,
	wangdicheng <wangdicheng@...inos.cn>
Subject: Re: [PATCH 1/2] ALSA: hda/realtek: Accelerate the front MIC charging and discharging of the 897 codec

On Mon, 04 Aug 2025 05:05:17 +0200,
wangdich9700@....com wrote:
> 
> From: wangdicheng <wangdicheng@...inos.cn>
> 
> The front MIC capacitance of the Inspur board is too large, resulting in a longer charging and discharging time required,
> which in turn prevents recording for 5 seconds before startup.
> Therefore, software is used to increase the delay by 2 seconds to avoid this issue.

First off, the HD-audio code was replaced in the latest Linus tree to
sound/hda/* directories, so please adapt the patches accordingly.

About the code change:

- The 2.5 seconds wait is way too long and inappropriate to be put in
  the resume callback.  It has to be fixed differently.

- Does it apply really to all devices with 0x10ec1304?  It's Realtek's
  vendor id, so this can match to many devices.

- Last but not least, it's not nice to have a code that depends on the
  certain vendor id there.  Again, please implement in a different way
  so that it can be handled in more device-specific code rather than
  the common function.


thanks,

Takashi

> 
> Signed-off-by: wangdicheng <wangdicheng@...inos.cn>
> ---
>  sound/pci/hda/patch_realtek.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
> index 877137cb09ac..88675eae9447 100644
> --- a/sound/pci/hda/patch_realtek.c
> +++ b/sound/pci/hda/patch_realtek.c
> @@ -1001,6 +1001,14 @@ static int alc_resume(struct hda_codec *codec)
>  	if (!spec->no_depop_delay)
>  		msleep(150); /* to avoid pop noise */
>  	codec->patch_ops.init(codec);
> +
> +	if (codec->core.subsystem_id == 0x10ec1304) {
> +		snd_hda_codec_write(codec, 0x19, 0, AC_VERB_SET_PIN_WIDGET_CONTROL, 0x04);
> +		msleep(50);
> +		snd_hda_codec_write(codec, 0x19, 0, AC_VERB_SET_PIN_WIDGET_CONTROL, 0x44);
> +		msleep(2000);
> +		snd_hda_codec_write(codec, 0x19, 0, AC_VERB_SET_PIN_WIDGET_CONTROL, PIN_VREF80);
> +	}
>  	snd_hda_regmap_sync(codec);
>  	hda_call_check_power_status(codec, 0x01);
>  	return 0;
> -- 
> 2.25.1
>