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Date:   Thu, 3 Nov 2022 16:29:44 +0100
From:   Johan Hovold <johan@kernel.org>
To:     Marek Szyprowski <m.szyprowski@samsung.com>
Cc:     Stefan Agner <stefan@agner.ch>,
        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
Subject: Re: [PATCH stable-5.15 3/3] usb: dwc3: disable USB core PHY
 management
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On Thu, Nov 03, 2022 at 04:18:12PM +0100, Marek Szyprowski wrote:
> Hi Johan,
> 
> On 03.11.2022 15:49, Johan Hovold wrote:
> > On Thu, Oct 27, 2022 at 02:45:15PM +0200, Johan Hovold wrote:
> >> On Wed, Oct 26, 2022 at 03:11:00PM +0200, Stefan Agner wrote:
> >>> The user reports the S-ATA disk is *not* recognized with that patch
> >>> applied.
> >> I just noticed a mistake in the instrumentation patch I sent you. Could
> >> you try moving the calibrations calls after dwc3_host_init() (e.g. as in
> >> the second chunk in the diff below)?
> >>
> >> As mentioned in the commit message for a0a465569b45 ("usb: dwc3: remove
> >> generic PHY calibrate() calls"), this may not work if the xhci-plat
> >> driver is built as a module and there are some corner cases that it does
> >> not cover.
> >>
> >> It seems we should revert the offending commit and then try to find some
> >> time to untangle this mess, but please check if the below addresses the
> >> issue first so we know what the problem is.
> >>
> >> I'll prepare a revert in the meantime.
> > I've now posted the revert, but please do check if the below patch was
> > enough to resolve the immediate issue.
> 
> The below patch was a half-fix. It worked only if both dwc3 and 
> xhci_plat_hcd were compiled into the kernel. Afair Debian-based distros 
> used xhci compiled as a module, so this didn't work for that case due to 
> timing issues.

Yeah, I mentioned that above too. The intention here was just to confirm
the hypothesis that the regression was due to the missing calibration
calls.

Johan