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 <20210805075401.21170-1-chihhao.chen@mediatek.com>
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From:   Geraldo Nascimento <geraldogabriel@gmail.com>
Date:   Thu, 5 Aug 2021 15:50:58 +0000
Message-ID: <CAEsQvcsvbJdgvAOxkv_kbLohGi676Zrgz4XSFW2o3CWU3Q68Dg@mail.gmail.com>
Subject: Re: [PATCH] ALSA: usb-audio: fix incorrect clock source setting
To:     chihhao chen <chihhao.chen@mediatek.com>
Cc:     alsa-devel@alsa-project.org, damien@zamaudio.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com,
        tiwai@suse.com, Takashi Iwai <tiwai@suse.de>,
        wsd_upstream@mediatek.com
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On Thu, Aug 5, 2021 at 7:54 AM <chihhao.chen@mediatek.com> wrote:
>
> From: chihhao chen <chihhao.chen@mediatek.com>
>
> Hi Geraldo Nascimento,

Hi Chihhao Chen!

>
> For echo test, it means we use this earphone to receive and play sounds at the same time.
> We found in this case serious noise problem happens.
>

That's what I understood initially, and only a little later I became
afraid echo test was the name of the debugging technique you used :)

Thanks for the clarification.

> Log as follows with your patch
> <6>[  175.960387][T401365] __uac_clock_find_source: Clock Selector 0xc has pin 2 selected
> <6>[  175.966980][T401365] __uac_clock_find_source: Clock Selector 0xb has pin 2 selected
> <6>[  176.026251][T400354] __uac_clock_find_source: Clock Selector 0xc has pin 1 selected
> <6>[  176.032406][T400354] __uac_clock_find_source: Clock Selector 0xb has pin 1 selected
>
> There is no noise and I think this should be a firmware bug.

From the log I'm afraid my worst assumptions were right.

Regardless of which Clock Selector we want to set, the firmware will
always set them both.

We should contact Samsung now that we have at least a sketch of a bug report...

Thanks,
Geraldo Nascimento

>
> Thanks
> Chihhao
>