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Message-ID: <8301c7f7-4c63-5681-af53-9edc67d96d17@gmail.com>
Date:   Sat, 6 Nov 2021 01:32:32 +0800
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Subject: Re: [PATCH] xhci: Fix USB 3.1 enumeration issues by increasing
 roothub power-on-good delay
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To:     Mathias Nyman <mathias.nyman@linux.intel.com>
Cc:     chunfeng.yun@mediatek.com, matthias.bgg@gmail.com,
        nishadkamdar@gmail.com, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, eddie.hung@mediatek.com,
        Alan Stern <stern@rowland.harvard.edu>,
        Greg KH <gregkh@linuxfoundation.org>
References: <20211105133050.GA1590803@rowland.harvard.edu>
 <20211105160036.549516-1-mathias.nyman@linux.intel.com>
 <96925c96-0f87-f110-e279-5b669337948a@linux.intel.com>
From:   "Walt Jr. Brake" <mr.yming81@gmail.com>
In-Reply-To: <96925c96-0f87-f110-e279-5b669337948a@linux.intel.com>
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On 6/11/2021 00:09, Mathias Nyman wrote:
> On 5.11.2021 18.00, Mathias Nyman wrote:
>> Some USB 3.1 enumeration issues were reported after the hub driver removed
>> the minimum 100ms limit for the power-on-good delay.
>>
>> Since commit 90d28fb53d4a ("usb: core: reduce power-on-good delay time of
>> root hub") the hub driver sets the power-on-delay based on the
>> bPwrOn2PwrGood value in the hub descriptor.
>>
>> xhci driver has a 20ms bPwrOn2PwrGood value for both roothubs based
>> on xhci spec section 5.4.8, but it's clearly not enough for the
>> USB 3.1 devices, causing enumeration issues.
>>
>> Tests indicate full 100ms delay is needed.
>>
>> Reported-by: Walt Jr. Brake <mr.yming81@gmail.com>
>> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
>>
> Walt Jr Brake, just to be sure could you test this one as well?
>
> As Alan suggested this sets 100ms for the USB 3 roothub but
> keeps the 20ms for the USB 2 roothub.
>
> Thanks
> -Mathias

Yes I tested, it works too.