linux-kernel - Re: [RFC]sound:usb:mixer.c: Solving 'Generic AB13X USB Audio' Unlikely volume range.

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Message-ID: <CAJE-K+AFBeEtK_e66r2VkeeayQW_H9H69uDQvtbAEKgQZ1QVHA@mail.gmail.com>
Date: Tue, 30 Sep 2025 19:16:32 +0530
From: Sidharth Seela <sidharthseela@...il.com>
To: Takashi Iwai <tiwai@...e.de>
Cc: perex@...ex.cz, tiwai@...e.com, zhujun2@...s.chinamobile.com, 
	kuninori.morimoto.gx@...esas.com, linux-sound@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [RFC]sound:usb:mixer.c: Solving 'Generic AB13X USB Audio'
 Unlikely volume range.

Thankyou Takashi for your reply,

On Mon, Sep 29, 2025 at 8:51 PM Takashi Iwai <tiwai@...e.de> wrote:
> An oft-seen firmware bug is that it provides the wrong mixer range
> that confuses the driver.  USB audio firmware should provide the above
> volume range in 1/256 dB level.

If possible, could you explain/ point me to a doc regarding cval->max,
cval->min,
and cval->res and its meanings, its relation to power and dB.


> Try to figure out the volume level and you'd need to hard-code the
> actual volume range there for your device
.
I am able to change the values and load in the module. But unable to exactly
understand how the values are related.

-- 
Thanks,
Sidharth Seela
www.realtimedesign.org