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From: "Stanley Chang[昌育德]" <stanley_chang@realtek.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>,
	Douglas Anderson <dianders@chromium.org>,
	Vincent Mailhol <mailhol.vincent@wanadoo.fr>,
	Bhuvanesh Surachari <Bhuvanesh_Surachari@mentor.com>,
	Mathias Nyman <mathias.nyman@linux.intel.com>,
	Flavio Suligoi <f.suligoi@asem.it>, Ray Chi <raychi@google.com>,
	Michael Grzeschik <m.grzeschik@pengutronix.de>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v1] usb: phy: add usb phy notify port status API
Date: Fri, 21 Apr 2023 08:40:05 +0000	[thread overview]
Message-ID: <fdf65c4eca9b420bb1ed29edb66482fb@realtek.com> (raw)
In-Reply-To: <ZEJHdCpLZ7f0946B@kroah.com>


> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index
> > 97a0f8faea6e..b4fbbeae1927 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -614,6 +614,19 @@ static int hub_ext_port_status(struct usb_hub *hub,
> int port1, int type,
> >               ret = 0;
> >       }
> >       mutex_unlock(&hub->status_mutex);
> > +
> > +     if (!ret) {
> > +             struct usb_device *hdev = hub->hdev;
> > +
> > +             if (hdev && !hdev->parent) {
> 
> How can you have a device without a parent?  And why does it matter?

If the hub is a root hub, the parent of hub will be NULL.
And we only send the port status to phy driver for root hub.
> 
> And how could hdev be NULL?  And if it can change to be NULL, what prevents
> it from changing right after you checked for it?
> 

It is right. hdev is never NULL, this is a redundant check.

Thanks,
Stanley

      reply	other threads:[~2023-04-21  8:40 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-21  8:03 [PATCH v1] usb: phy: add usb phy notify port status API Stanley Chang
2023-04-21  8:19 ` Greg Kroah-Hartman
2023-04-21  8:32   ` Stanley Chang[昌育德]
2023-04-21 11:08     ` Greg Kroah-Hartman
2023-04-21 11:19       ` Stanley Chang[昌育德]
2023-04-21  8:21 ` Greg Kroah-Hartman
2023-04-21  8:40   ` Stanley Chang[昌育德] [this message]

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