Messages in this thread | | | Date | Thu, 9 Nov 2023 09:15:36 +0000 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH net 1/1] net: stmmac: fix MAC and phylink mismatch issue after resume with STMMAC_FLAG_USE_PHY_WOL enabled |
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On Thu, Nov 09, 2023 at 01:00:27PM +0800, Gan Yi Fang wrote: > From: "Gan, Yi Fang" <yi.fang.gan@intel.com> > > The issue happened when flag STMMAC_FLAG_USE_PHY_WOL is enabled. > It can be reproduced with steps below: > 1. Advertise only one speed on the host > 2. Enable the WoL on the host > 3. Suspend the host > 4. Wake up the host > > When the WoL is disabled, both the PHY and MAC will suspend and wake up > with everything configured well. When WoL is enabled, the PHY needs to be > stay awake to receive the signal from remote client but MAC will enter > suspend mode. > > When the MAC resumes from suspend, phylink_resume() will call > phylink_start() to start the phylink instance which will trigger the > phylink machine to invoke the mac_link_up callback function. The > stmmac_mac_link_up() will configure the MAC_CTRL_REG based on the current > link state. Then the stmmac_hw_setup() will be called to configure the MAC. > > This sequence might cause mismatch of the link state between MAC and > phylink. This patch moves the phylink_resume() after stmamc_hw_setup() to > ensure the MAC is initialized before phylink is being configured.
Isn't this going to cause problems?
stmamc_hw_setup() calls stmmac_init_dma_engine(), which then calls stmmac_reset() - and stmmac_reset() can fail if the PHY clock isn't running, which is why phylink_resume() gets called before this.
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