From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH] mvneta: implement SGMII-based in-band link state signaling Date: Thu, 02 Apr 2015 18:03:53 -0700 Message-ID: <551DE6F9.9020903@gmail.com> References: <551AA02B.2050104@list.ru> <20150402.205131.1699226515102250937.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@free-electrons.com To: David Miller , stsp@list.ru Return-path: In-Reply-To: <20150402.205131.1699226515102250937.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 02/04/15 17:51, David Miller wrote: > From: Stas Sergeev > Date: Tue, 31 Mar 2015 16:24:59 +0300 > >> @@ -2590,6 +2651,7 @@ static int mvneta_mdio_probe(struct mvneta_port *pp) >> >> static void mvneta_mdio_remove(struct mvneta_port *pp) >> { >> + fixed_phy_set_link_update(pp->phy_dev, NULL); > > I do not see any other driver doing this on shutdown. > Please show me why it is necessary. The primary reason is that if you do not do that, past the point where you call phy_disconnect(), we stop the PHY state machine, detach from the net_device, such that it won't invoke the adjust_link callback anymore. The fixed PHY driver, though will still keep calling the fixed_link_update callback asking the driver whether the link parameters need to be updated, and that will just cause a NULL pointer de-reference phydev->attached_dev, since we are now in detached state. I guess another way to fix that is to look for the PHY state in fixed_mdio_read() and do nothing if it is PHY_HALTED. > > And if it is, all other drivers registering a fixed phy link update > function need to be adjusted to do the same thing. > I think the bcmgenet driver is now doing this as a result of Petri's latest changes, and I meant to comment on that before the patch got in. drivers/net/dsa/bcm_sf2.c has a similar construct but does not invoke phy_disconnect() nor can be rmmod'd, so a lesser issue. -- Florian