linux-kernel - Re: [PATCH] ASoC: tegra: Add master volume/mute control support

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Message-ID: <f709fcff-1bd4-1251-1471-aad01fdfdedd@perex.cz>
Date:   Fri, 29 Oct 2021 17:26:34 +0200
From:   Jaroslav Kysela <perex@...ex.cz>
To:     Sameer Pujar <spujar@...dia.com>, broonie@...nel.org,
        lgirdwood@...il.com, tiwai@...e.com
Cc:     jonathanh@...dia.com, thierry.reding@...il.com,
        alsa-devel@...a-project.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ASoC: tegra: Add master volume/mute control support

On 29. 10. 21 17:08, Sameer Pujar wrote:
> 
> 
> On 10/26/2021 11:53 AM, Sameer Pujar wrote:
>>
>>
>> On 10/25/2021 6:28 PM, Jaroslav Kysela wrote:
>>> On 25. 10. 21 13:06, Sameer Pujar wrote:
>>>
>>>> @@ -150,11 +186,22 @@ static int tegra210_mvc_put_mute(struct
>>>> snd_kcontrol *kcontrol,
>>>
>>> ...
>>>>
>>>>        return 1;
>>>
>>> It's a bit unrelated comment to this change, but it may be worth to
>>> verify all
>>> kcontrol put callbacks in the tegra code. Ensure that value 1 is
>>> returned only
>>> when something was really changed in hardware.
> 
> There are cases when the mixer control update is not immediately written
> to HW, instead the update is ACKed (stored in variable) and writen to HW
> at a later point of time. Do these cases qualify for "return 1" as well?

Yes - assuming that the get callback returns the cached value. The get/put 
implementation should be consistent from the caller view. The driver 
implementation (delayed write) is a separate thing.

						Jaroslav

-- 
Jaroslav Kysela <perex@...ex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.