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Message-ID: <YYVYrksU5/aCB3Fd@kroah.com>
Date: Fri, 5 Nov 2021 17:15:42 +0100
From: Greg KH <gregkh@...uxfoundation.org>
To: Mathias Nyman <mathias.nyman@...ux.intel.com>
Cc: stern@...land.harvard.edu, mr.yming81@...il.com,
chunfeng.yun@...iatek.com, matthias.bgg@...il.com,
nishadkamdar@...il.com, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org, eddie.hung@...iatek.com
Subject: Re: [PATCH] xhci: Fix USB 3.1 enumeration issues by increasing
roothub power-on-good delay
On Fri, Nov 05, 2021 at 06:00:36PM +0200, 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@...il.com>
> Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
So this needs:
Fixes: 90d28fb53d4a ("usb: core: reduce power-on-good delay time of root hub")
right?
thanks,
greg k-h
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