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Date:   Mon, 17 Jan 2022 08:18:53 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc:     stern@rowland.harvard.edu, mathias.nyman@linux.intel.com,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Bixuan Cui <cuibixuan@huawei.com>,
        Rajat Jain <rajatja@google.com>, Andrew Lunn <andrew@lunn.ch>,
        Chris Chiu <chris.chiu@canonical.com>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] usb: core: Bail out when port is stuck in reset loop
Message-ID: <YeUYXbIsZV1GY3wa@kroah.com>
References: <20211230052811.650191-1-kai.heng.feng@canonical.com>
 <CAAd53p6ev+yQT+jf32UrTMWQXwDPYtmZSrW0zCQnKuUaBbtXUg@mail.gmail.com>
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On Mon, Jan 17, 2022 at 11:00:05AM +0800, Kai-Heng Feng wrote:
> On Thu, Dec 30, 2021 at 1:28 PM Kai-Heng Feng
> <kai.heng.feng@canonical.com> wrote:
> >
> > Unplugging USB device may cause an incorrect warm reset loop and the
> > port can no longer be used:
> > [  143.039019] xhci_hcd 0000:00:14.0: Port change event, 2-3, id 19, portsc: 0x4202c0
> > [  143.039025] xhci_hcd 0000:00:14.0: handle_port_status: starting usb2 port polling.
> > [  143.039051] hub 2-0:1.0: state 7 ports 10 chg 0000 evt 0008
> > [  143.039058] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x4202c0, return 0x4102c0
> > [  143.039092] xhci_hcd 0000:00:14.0: clear port3 connect change, portsc: 0x4002c0
> > [  143.039096] usb usb2-port3: link state change
> > [  143.039099] xhci_hcd 0000:00:14.0: clear port3 link state change, portsc: 0x2c0
> > [  143.039101] usb usb2-port3: do warm reset
> > [  143.096736] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2b0, return 0x2b0
> > [  143.096751] usb usb2-port3: not warm reset yet, waiting 50ms
> > [  143.131500] xhci_hcd 0000:00:14.0: Can't queue urb, port error, link inactive
> > [  143.138260] xhci_hcd 0000:00:14.0: Port change event, 2-3, id 19, portsc: 0x2802a0
> > [  143.138263] xhci_hcd 0000:00:14.0: handle_port_status: starting usb2 port polling.
> > [  143.160756] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2802a0, return 0x3002a0
> > [  143.160798] usb usb2-port3: not warm reset yet, waiting 200ms
> >
> > The port status is PP=1, CCS=0, PED=0, PLS=Inactive, which is Error
> > state per "USB3 Root Hub Port State Machine". It's reasonable to perform
> > warm reset several times, but if the port is still not enabled after
> > many attempts, consider it's gone and treat it as disconnected.
> >
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> 
> A gentle ping...

It's the merge window, I can't do anything, sorry.  Please wait until
after 5.17-rc1 is out.

thanks,

greg k-h