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Message-ID: <ac7918ea-ae67-fd0d-bb0f-b0093908f6d7@samsung.com>
Date:   Fri, 28 Oct 2022 15:46:01 +0200
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Subject: Re: [PATCH stable-5.15 3/3] usb: dwc3: disable USB core PHY
 management
To:     Stefan Agner <stefan@agner.ch>, Johan Hovold <johan@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, linux-kernel@vger.kernel.org,
        Johan Hovold <johan+linaro@kernel.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        stable <stable@kernel.org>, regressions@lists.linux.dev,
        krzk@kernel.org
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From:   Marek Szyprowski <m.szyprowski@samsung.com>
In-Reply-To: <808bdba846bb60456adf10a3016911ee@agner.ch>
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References: <20220906120702.19219-1-johan@kernel.org>
        <20220906120702.19219-4-johan@kernel.org>
        <CGME20221018152853eucas1p2bd3531388625cf11f8b514bb9cc35e76@eucas1p2.samsung.com>
        <808bdba846bb60456adf10a3016911ee@agner.ch>
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Dear All,

On 18.10.2022 17:27, Stefan Agner wrote:
> Hi Johan,
>
> On 2022-09-06 14:07, Johan Hovold wrote:
>> From: Johan Hovold <johan+linaro@kernel.org>
>>
>> commit 6000b8d900cd5f52fbcd0776d0cc396e88c8c2ea upstream.
>>
>> The dwc3 driver manages its PHYs itself so the USB core PHY management
>> needs to be disabled.
>>
>> Use the struct xhci_plat_priv hack added by commits 46034a999c07 ("usb:
>> host: xhci-plat: add platform data support") and f768e718911e ("usb:
>> host: xhci-plat: add priv quirk for skip PHY initialization") to
>> propagate the setting for now.
> [adding also Samsung/ODROID device tree authors Krzysztof and Marek]
>
> For some reason, this commit seems to break detection of the USB to
> S-ATA controller on ODROID-HC1 devices (Exynos 5422).
>
> We have a known to work OS release of v5.15.60, and known to not be
> working of v5.15.67. By reverting suspicious commits, I was able to
> pinpoint the problem to this particular commit.
>
> >From what I understand, on that particular hardware the S-ATA controller
> power is controlled via the V-BUS signal VBUSCTRL_U2 (Schematic [1]).
> Presumably this signal is no longer controlled with this change.
>
> This came up in our HAOS issue #2153 [2].

I confirm this issue and I've managed to reproduce it locally. The 
mainline is also affected. I will try to prepare a proper patch soon.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland