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Date:   Mon, 18 Feb 2019 10:39:02 -0500 (EST)
From:   Alan Stern <stern@rowland.harvard.edu>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc:     linux-kernel@vger.kernel.org, <stable@vger.kernel.org>,
        Mathias Nyman <mathias.nyman@linux.intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH 4.4 026/143] usb: hub: delay hub autosuspend if USB3 port
 is still link training
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On Mon, 18 Feb 2019, Greg Kroah-Hartman wrote:

> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> [ Upstream commit e86108940e541febf35813402ff29fa6f4a9ac0b ]
> 
> When initializing a hub we want to give a USB3 port in link training
> the same debounce delay time before autosuspening the hub as already
> trained, connected enabled ports.
> 
> USB3 ports won't reach the enabled state with "current connect status" and
> "connect status change" bits set until the USB3 link training finishes.
> 
> Catching the port in link training (polling) and adding the debounce delay
> prevents unnecessary failed attempts to autosuspend the hub.
> 
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

We should be careful with this commit; it has caused problems for some
people.  Mathias has been working to fix them, but this commit
shouldn't go into -stable until the fixes are also ready to go.

Alan Stern