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

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Message-ID: <YLq6G9luZrXW5vry@lunn.ch>
Date:   Sat, 5 Jun 2021 01:41:15 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Oleksij Rempel <o.rempel@...gutronix.de>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>, kernel@...gutronix.de,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH net-next v1 7/7] usbnet: run unbind() before
 unregister_netdev()

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.

      Andrew