From: "Russell King (Oracle)" <firstname.lastname@example.org> To: Joakim Zhang <email@example.com> Cc: Vladimir Oltean <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, dl-linux-imx <email@example.com> Subject: Re: [PATCH] net: stmmac: fix MAC not working when system resume back with WoL enabled Date: Thu, 2 Sep 2021 11:49:43 +0100 [thread overview] Message-ID: <20210902104943.GD22278@shell.armlinux.org.uk> (raw) In-Reply-To: <DB8PR04MB67954F4650408025E6D4EE2AE6CE9@DB8PR04MB6795.eurprd04.prod.outlook.com> On Thu, Sep 02, 2021 at 10:26:13AM +0000, Joakim Zhang wrote: > > Hi Russell, > > Thanks a lot! > > > -----Original Message----- > > From: Russell King <firstname.lastname@example.org> > > Sent: 2021年9月2日 16:32 > > To: Joakim Zhang <email@example.com> > > Cc: Vladimir Oltean <firstname.lastname@example.org>; email@example.com; > > firstname.lastname@example.org; email@example.com; > > firstname.lastname@example.org; email@example.com; firstname.lastname@example.org; > > email@example.com; firstname.lastname@example.org; email@example.com; > > firstname.lastname@example.org; dl-linux-imx <email@example.com> > > Subject: Re: [PATCH] net: stmmac: fix MAC not working when system resume > > back with WoL enabled > > > > On Thu, Sep 02, 2021 at 07:28:44AM +0000, Joakim Zhang wrote: > > > > > > Hi Russell, > > > > > > > -----Original Message----- > > > > From: Russell King <firstname.lastname@example.org> > > > > Sent: 2021年9月1日 21:26 > > > > To: Joakim Zhang <email@example.com> > > > > Cc: Vladimir Oltean <firstname.lastname@example.org>; email@example.com; > > > > firstname.lastname@example.org; email@example.com; > > > > firstname.lastname@example.org; email@example.com; firstname.lastname@example.org; > > > > email@example.com; firstname.lastname@example.org; email@example.com; > > > > firstname.lastname@example.org; dl-linux-imx <email@example.com> > > > > Subject: Re: [PATCH] net: stmmac: fix MAC not working when system > > > > resume back with WoL enabled > > > > > > > > This means you need to have the phy <-> mac link up during suspend, > > > > and in that case, yes, you do not want to call > > > > phylink_stop() or phylink_start(). > > > > > > I have a question here, why need to have the phy<->mac link up during > > suspend? > > > > You need the link up because I think from reading the code, it is _not_ the PHY > > that is triggering the wakeup in the configuration you are using, but the MAC. > > > > If the link is down, the PHY can't pass the received packet to the MAC, and the > > MAC can't recognise the magic packet. > > Per my understanding, if use PHY-based wakeup, PHY should be active, and MAC can be > totally suspended. When PHY receive the magic packets, it will generate a signal via wakeup > PIN (PHY seems all have such PIN) to inform SoC, we can use this to wake up the system. > Please correct me if I misunderstand. Correct. > > FEC doesn't have this. FEC relies purely on the PHY detecting the magic packet, > > which is much more power efficient, because it means the MAC doesn't need > > to be powered up and operational while the rest of the system is suspended. > > AFAIK, FEC also use the MAC-based wakeup, when enable FEC WoL feature, it will > keep MAC receive logic active, PHY pass the received packets to MAC, if MAC detects > the magic packets, it will generate an interrupt to wake up the system. You're right. However, as the PHY is not configured for WoL with FEC, and fec_suspend() unconditionally calls phy_stop() which will place the PHY into suspend mode. Maybe the PHY driver there has a NULL phydrv->suspend method? However, I see that at803x has suspend methods (which I believe is the PHY that gets used with i.MX products) which will power down the PHY. So, how does this work with FEC - because right now I can't see it working, but you say it does. I think we need to understand how FEC is working here, and we need a deeper understanding why stmmac isn't working. I don't have any iMX systems that support WoL, so this isn't something I can test. (SolidRun's i.MX platforms do not support any kind of system power down, so suspend isn't supported.) -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2021-09-02 10:50 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 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) [this message] 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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