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From:   Felipe Balbi <balbi@kernel.org>
To:     Sandeep Maheswaram <sanm@codeaurora.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Pratham Pratap <prathampratap@codeaurora.org>,
        Jack Pham <jackp@codeaurora.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        Doug Anderson <dianders@chromium.org>
Subject: Re: Regarding usb dwc3 core shutdown callback
Date:   Thu, 26 Aug 2021 13:43:11 +0300
In-reply-to: <eb975a76-1482-f502-4dc1-7993cc3f30d0@codeaurora.org>
Message-ID: <87eeaga39m.fsf@kernel.org>
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Hi,

Sandeep Maheswaram <sanm@codeaurora.org> writes:
>> (why isn't this email plain/text? Content Type was set to multipart
>> alternative, please configure your email client correctly :-)
>>
>> While at that, also make sure to break lines at 80-columns)
>>
>> Sandeep Maheswaram <sanm@codeaurora.org> writes:
>>> Hi,
>>>
>>> Earlier I have posted the patch for usb dwc3 core shutdown callback
>>>
>>> https://lore.kernel.org/linux-arm-msm/1618380209-20114-1-git-send-email-sanm@codeaurora.org/
>>>
>>> and it was reverted due to issues.
>> Right, as should be expected when we find regressions
>>
>>> https://lore.kernel.org/linux-usb/20210603151742.298243-1-alexandru.elisei@arm.com/
>>>
>>> As we already have shutdown callback in xhci plat driver where we halt
>>> the controller, so there will be no transactions with usb devices.
>>>
>>> https://lore.kernel.org/linux-usb/20200306092328.41253-1-ran.wang_1@nxp.com/
>>>
>>> So I think dwc3 core shutdown may not be required at least when we are
>>> using host mode. Let me know your opinion about this.
>> If that's the case, then sure. Please validate the condition, though,
>> and kindly report back on your findings
>
> I have enabled couple of logs in shutdown path and see no URBs
> enqueued after xhci shut down.
>
> Hope this is enough for validation . Please suggest if anything more I
> could do.

how about writing a little script to kexec into another kernel for a few
hundred iterations and make sure things still work after all that?

-- 
balbi