Subject: Re: [PATCH 1/3] ALSA: hda/tegra: Skip reset on BPMP devices
From:   Dmitry Osipenko <digetx@gmail.com>
To:     Sameer Pujar <spujar@nvidia.com>, tiwai@suse.com,
        broonie@kernel.org, lgirdwood@gmail.com, robh+dt@kernel.org,
        thierry.reding@gmail.com, perex@perex.cz
Cc:     jonathanh@nvidia.com, alsa-devel@alsa-project.org,
        devicetree@vger.kernel.org, linux-tegra@vger.kernel.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
References: <1638858770-22594-1-git-send-email-spujar@nvidia.com>
 <1638858770-22594-2-git-send-email-spujar@nvidia.com>
 <7742adae-cdbe-a9ea-2cef-f63363298d73@gmail.com>
 <2f29f787-7c77-a56e-3b90-0fc452fd1c88@gmail.com>
Message-ID: <9c21aa0d-b7e6-17b8-cd1a-f12a2b2a1a57@gmail.com>
Date:   Tue, 7 Dec 2021 13:58:41 +0300
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07.12.2021 13:44, Dmitry Osipenko пишет:
> 07.12.2021 13:22, Dmitry Osipenko пишет:
>> 07.12.2021 09:32, Sameer Pujar пишет:
>>> HDA regression is recently reported on Tegra194 based platforms.
>>> This happens because "hda2codec_2x" reset does not really exist
>>> in Tegra194 and it causes probe failure. All the HDA based audio
>>> tests fail at the moment. This underlying issue is exposed by
>>> commit c045ceb5a145 ("reset: tegra-bpmp: Handle errors in BPMP
>>> response") which now checks return code of BPMP command response.

I see that this BPMP commit already has been reverted. There is no
problem in this hda_tegra driver at all.

>>> The failure can be fixed by avoiding above reset in the driver,
>>> but the explicit reset is not necessary for Tegra devices which
>>> depend on BPMP. On such devices, BPMP ensures reset application
>>> during unpowergate calls. Hence skip reset on these devices
>>> which is applicable for Tegra186 and later.
>>
>> The power domain is shared with the display, AFAICS. The point of reset
>> is to bring h/w into predictable state. It doesn't make sense to me to
>> skip the reset.
>>
>> If T194+ doesn't have hda2codec_2x reset, then don't request that reset
>> for T194+.
>>
> 
> I don't see the problem in the driver. It's only the device-tree that is
> wrong. This hda_tegra.c patch should be unneeded, please fix only the
> device-tree.
>