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

Mathias Nyman
2021-11-05T16:13:54Z

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