Re: [PATCH] xhci: Fix USB 3.1 enumeration issues by increasing roothub power-on-good delay

Mathias Nyman
2021-11-05T19:40:04Z

On 5.11.2021 19.32, Walt Jr. Brake wrote:
> 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.
>

Thank you
-Mathias