linux-kernel - Re: [PATCH net-next v1 7/7] usbnet: run unbind() before unregister

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Date:   Mon, 7 Jun 2021 10:04:04 +0200
From:   Oleksij Rempel <o.rempel@...gutronix.de>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     netdev@...r.kernel.org, linux-usb@...r.kernel.org,
        Russell King <linux@...linux.org.uk>,
        linux-kernel@...r.kernel.org, kernel@...gutronix.de,
        Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Heiner Kallweit <hkallweit1@...il.com>
Subject: Re: [PATCH net-next v1 7/7] usbnet: run unbind() before
 unregister_netdev()

On Sat, Jun 05, 2021 at 01:41:15AM +0200, Andrew Lunn wrote:
> On Fri, Jun 04, 2021 at 03:42:44PM +0200, Oleksij Rempel wrote:
> > unbind() is the proper place to disconnect PHY, but it will fail if
> > netdev is already unregistered.
> 
> O.K, this partially answers the question i was about to ask for the
> previous patch.
> 
> void phy_start(struct phy_device *phydev)
> {
> 	mutex_lock(&phydev->lock);
> 
> 	if (phydev->state != PHY_READY && phydev->state != PHY_HALTED) {
> 		WARN(1, "called from state %s\n",
> 		     phy_state_to_str(phydev->state));
> 		goto out;
> 	}
> 
> By skipping phy_error(), phydev->state is not set to PHY_HALTED. So if
> you try to start the phy again, without disconnecting it, it looks
> like there could be a problem.
> 
> But with this patch, i assume the PHY will always be disconnected and
> later reconnected when the device is replugged.

Yes. The PHY is disconnected and the PHY driver is unbinded.

Regards,
Oleksij
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