Messages in this thread | | | Date | Tue, 3 Jan 2023 09:46:38 +0000 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH 1/2] net: phylink: add a function to resume phy alone to fix resume issue with WoL enabled |
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On Wed, Dec 21, 2022 at 04:01:43PM +0800, Clark Wang wrote: > Issue we met: > On some platforms, mac cannot work after resumed from the suspend with WoL > enabled. > > The cause of the issue: > 1. phylink_resolve() is in a workqueue which will not be executed immediately. > This is the call sequence: > phylink_resolve()->phylink_link_up()->pl->mac_ops->mac_link_up() > For stmmac driver, mac_link_up() will set the correct speed/duplex... > values which are from link_state. > 2. In stmmac_resume(), it will call stmmac_hw_setup() after called the > phylink_resume(), because mac need phy rx_clk to do the reset. > stmmac_core_init() is called in function stmmac_hw_setup(), which will > reset the mac and set the speed/duplex... to default value. > Conclusion: Because phylink_resolve() cannot determine when it is called, it > cannot be guaranteed to be called after stmmac_core_init(). > Once stmmac_core_init() is called after phylink_resolve(), > the mac will be misconfigured and cannot be used. > > In order to avoid this problem, add a function called phylink_phy_resume() > to resume phy separately. This eliminates the need to call phylink_resume() > before stmmac_hw_setup(). > > Add another judgement before called phy_start() in phylink_start(). This way > phy_start() will not be called multiple times when resumes. At the same time, > it may not affect other drivers that do not use phylink_phy_resume(). > > Signed-off-by: Clark Wang <xiaoning.wang@nxp.com> > --- > drivers/net/phy/phylink.c | 21 ++++++++++++++++++++- > include/linux/phylink.h | 1 + > 2 files changed, 21 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c > index 09cc65c0da93..5bab59142579 100644 > --- a/drivers/net/phy/phylink.c > +++ b/drivers/net/phy/phylink.c > @@ -1939,7 +1939,7 @@ void phylink_start(struct phylink *pl) > } > if (poll) > mod_timer(&pl->link_poll, jiffies + HZ); > - if (pl->phydev) > + if (pl->phydev && pl->phydev->state < PHY_UP)
I'm really not happy with this - not only does this subvert the checks in phy_start(), it's a layering violation, and it delves into internals of phylib in an unprotected way.
-- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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