From: Vladimir Oltean <olteanv@gmail.com> To: Joakim Zhang <qiangqing.zhang@nxp.com> Cc: peppe.cavallaro@st.com, alexandre.torgue@foss.st.com, joabreu@synopsys.com, davem@davemloft.net, kuba@kernel.org, mcoquelin.stm32@gmail.com, linux@armlinux.org.uk, netdev@vger.kernel.org, andrew@lunn.ch, f.fainelli@gmail.com, hkallweit1@gmail.com, linux-imx@nxp.com Subject: Re: [PATCH] net: stmmac: fix MAC not working when system resume back with WoL enabled Date: Wed, 1 Sep 2021 12:21:49 +0300 [thread overview] Message-ID: <20210901092149.fmap4ac7jxf754ao@skbuf> (raw) In-Reply-To: <20210901090228.11308-1-qiangqing.zhang@nxp.com> On Wed, Sep 01, 2021 at 05:02:28PM +0800, Joakim Zhang wrote: > We can reproduce this issue with below steps: > 1) enable WoL on the host > 2) host system suspended > 3) remote client send out wakeup packets > We can see that host system resume back, but can't work, such as ping failed. > > After a bit digging, this issue is introduced by the commit 46f69ded988d > ("net: stmmac: Use resolved link config in mac_link_up()"), which use > the finalised link parameters in mac_link_up() rather than the > parameters in mac_config(). > > There are two scenarios for MAC suspend/resume: > > 1) MAC suspend with WoL disabled, stmmac_suspend() call > phylink_mac_change() to notify phylink machine that a change in MAC > state, then .mac_link_down callback would be invoked. Further, it will > call phylink_stop() to stop the phylink instance. When MAC resume back, > firstly phylink_start() is called to start the phylink instance, then > call phylink_mac_change() which will finally trigger phylink machine to > invoke .mac_config and .mac_link_up callback. All is fine since > configuration in these two callbacks will be initialized. > > 2) MAC suspend with WoL enabled, phylink_mac_change() will put link > down, but there is no phylink_stop() to stop the phylink instance, so it > will link up again, that means .mac_config and .mac_link_up would be > invoked before system suspended. After system resume back, it will do > DMA initialization and SW reset which let MAC lost the hardware setting > (i.e MAC_Configuration register(offset 0x0) is reset). Since link is up > before system suspended, so .mac_link_up would not be invoked after > system resume back, lead to there is no chance to initialize the > configuration in .mac_link_up callback, as a result, MAC can't work any > longer. Have you tried putting phylink_stop in .suspend, and phylink_start in .resume? > > Above description is what I found when debug this issue, this patch is > just revert broken patch to workaround it, at least make MAC work when > system resume back with WoL enabled. > > Said this is a workaround, since it has not resolve the issue completely. > I just move the speed/duplex/pause etc into .mac_config callback, there are > other configurations in .mac_link_up callback which also need to be > initialized to work for specific functions. > > Fixes: 46f69ded988d ("net: stmmac: Use resolved link config in mac_link_up()") > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com> > --- > > Broken patch cannot be reverted directly, so manually modified it. > > I also tried to fix in other ways, but failed to find a better solution, > any suggestions would be appreciated. Thanks. > > Joakim Do you know exactly why it used to work prior to this patch?
next prev parent reply other threads:[~2021-09-01 9:21 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-01 9:02 Joakim Zhang 2021-09-01 9:13 ` Russell King (Oracle) 2021-09-01 10:21 ` Joakim Zhang 2021-09-01 12:56 ` Russell King (Oracle) 2021-09-02 7:01 ` Joakim Zhang 2021-09-01 15:40 ` Heiner Kallweit 2021-09-02 7:35 ` Joakim Zhang 2021-09-01 9:21 ` Vladimir Oltean [this message] 2021-09-01 10:25 ` Joakim Zhang 2021-09-01 10:56 ` Vladimir Oltean 2021-09-01 11:42 ` Joakim Zhang 2021-09-01 13:25 ` Russell King (Oracle) 2021-09-02 7:28 ` Joakim Zhang 2021-09-02 8:32 ` Russell King (Oracle) 2021-09-02 10:26 ` Joakim Zhang 2021-09-02 10:49 ` Russell King (Oracle) 2021-09-02 11:15 ` Joakim Zhang 2021-09-02 12:24 ` Andrew Lunn 2021-09-03 6:51 ` Joakim Zhang 2021-09-03 8:01 ` Russell King (Oracle) 2021-09-03 8:39 ` Joakim Zhang 2021-09-03 9:32 ` Russell King (Oracle) 2021-09-03 11:04 ` Joakim Zhang 2021-09-03 12:01 ` Russell King (Oracle) 2021-09-03 20:12 ` Russell King - ARM Linux admin 2021-09-06 2:29 ` Joakim Zhang 2021-09-06 9:34 ` Russell King (Oracle) 2021-09-06 10:41 ` Joakim Zhang 2021-09-06 11:21 ` Russell King (Oracle) 2021-09-06 13:23 ` Andrew Lunn 2021-09-07 8:52 ` Russell King (Oracle) 2021-09-06 2:21 ` Joakim Zhang
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