linux-kernel - Re: [PATCH 1/3] ALSA: hda/tegra: Skip reset on BPMP devices

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Message-ID: <7742adae-cdbe-a9ea-2cef-f63363298d73@gmail.com>
Date:   Tue, 7 Dec 2021 13:22:28 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Sameer Pujar <spujar@...dia.com>, tiwai@...e.com,
        broonie@...nel.org, lgirdwood@...il.com, robh+dt@...nel.org,
        thierry.reding@...il.com, perex@...ex.cz
Cc:     jonathanh@...dia.com, alsa-devel@...a-project.org,
        devicetree@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH 1/3] ALSA: hda/tegra: Skip reset on BPMP devices

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.
> 
> 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+.