Date:   Tue, 21 Dec 2021 09:30:02 -0500
From:   Alan Stern <stern@rowland.harvard.edu>
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc:     gregkh@linuxfoundation.org, mathias.nyman@linux.intel.com,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Andrew Lunn <andrew@lunn.ch>, Rajat Jain <rajatja@google.com>,
        Chris Chiu <chris.chiu@canonical.com>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] usb: core: Avoid doing warm reset on disconnect event
Message-ID: <YcHk6pam0plSFT3M@rowland.harvard.edu>
References: <20211126115652.1134230-1-kai.heng.feng@canonical.com>
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On Tue, Dec 21, 2021 at 11:35:25AM +0800, Kai-Heng Feng wrote:
> (
> 
> 
> On Fri, Nov 26, 2021 at 11:30 PM Alan Stern <stern@rowland.harvard.edu> wrote:
> > Why is it correct to skip doing a warm reset on a disconnected port here, but not
> > correct to skip doing a warm reset on a disconnected port in all the other places
> > where hub_port_warm_reset_required() gets called?
> 
> Can a disconnect event happens to other places other than port_event()?

A disconnect can happen at any time.  After all, users can unplug USB 
cables whenever they want.

Alan Stern