From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Iwai <tiwai@suse.de>
Subject: Re: Dell USB audio driver workaround
Date: Wed, 06 Apr 2016 10:56:54 +0200
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References: <6FAB7C47BCF00940BB0999A99BE3547A17A32FFC@RTITMBSV09.realtek.com.tw>
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To: Kailang <kailang@realtek.com>
Cc: " (alsa-devel@alsa-project.org)" <alsa-devel@alsa-project.org>
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On Wed, 06 Apr 2016 08:29:12 +0200,
Kailang wrote:
> 
> Hi Takashi,
> 
> Dell had USB dock.
> Maybe firmware issue, the master volume always keep at 0x57.
> Attach patch will fix it to keep at Max volume.
> 
> Could you help us to update it?

Well, I don't get how this patch works..

> diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
> index 4f85757..84d9a4e 100644
> --- a/sound/usb/mixer.c
> +++ b/sound/usb/mixer.c
> @@ -846,6 +846,12 @@ static void volume_control_quirks(struct usb_mixer_elem_info *cval,
>  {
>  	struct snd_usb_audio *chip = cval->head.mixer->chip;
>  	switch (chip->usb_id) {
> +	case USB_ID(0x0bda, 0x4014): /* Dell workaround */
> +		if (strstr(kctl->id.name, "Playback Volume") != NULL) {
> +			cval->min = 0x0000;
> +			cval->max = 0x0000;
> +		}
> +		break;

So, this means that this value has to be fixed to 0?
If yes, can't we simply remove this volume instead?


thanks,

Takashi