FAILED: patch "[PATCH] net: phy: Don't trigger state machine while in suspend" failed to apply to 4.9-stable tree
Subsystems (3)
[email protected]
maintainerThe patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 1758bde2e4aa5ff188d53e7d9d388bbb7e12eebb Mon Sep 17 00:00:00 2001
From: Lukas Wunner <[email protected]>
Date: Tue, 28 Jun 2022 12:15:08 +0200
Subject: [PATCH] net: phy: Don't trigger state machine while in suspend
Upon system sleep, mdio_bus_phy_suspend() stops the phy_state_machine(), but subsequent interrupts may retrigger it:
They may have been left enabled to facilitate wakeup and are not quiesced until the ->suspend_noirq() phase. Unwanted interrupts may hence occur between mdio_bus_phy_suspend() and dpm_suspend_noirq(), as well as between dpm_resume_noirq() and mdio_bus_phy_resume().
Retriggering the phy_state_machine() through an interrupt is not only undesirable for the reason given in mdio_bus_phy_suspend() (freezing it midway with phydev->lock held), but also because the PHY may be inaccessible after it's suspended: Accesses to USB-attached PHYs are blocked once usb_suspend_both() clears the can_submit flag and PHYs on PCI network cards may become inaccessible upon suspend as well.
Amend phy_interrupt() to avoid triggering the state machine if the PHY is suspended. Signal wakeup instead if the attached net_device or its parent has been configured as a wakeup source. (Those conditions are identical to mdio_bus_phy_may_suspend().) Postpone handling of the interrupt until the PHY has resumed.
Before stopping the phy_state_machine() in mdio_bus_phy_suspend(), wait for a concurrent phy_interrupt() to run to completion. That is necessary because phy_interrupt() may have checked the PHY's suspend status before the system sleep transition commenced and it may thus retrigger the state machine after it was stopped.
Likewise, after re-enabling interrupt handling in mdio_bus_phy_resume(), wait for a concurrent phy_interrupt() to complete to ensure that interrupts which it postponed are properly rerun.
The issue was exposed by commit 1ce8b37241ed ("usbnet: smsc95xx: Forward PHY interrupts to PHY driver to avoid polling"), but has existed since forever.
drivers/net/phy/phy.c +23 -0
@@ -31,6 +31,7 @@#include <linux/io.h> #include <linux/uaccess.h> #include <linux/atomic.h> +#include <linux/suspend.h> #include <net/netlink.h> #include <net/genetlink.h> #include <net/sock.h>
@@ -976,6 +977,28 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)struct phy_driver *drv = phydev->drv;irqreturn_t ret; +/* Wakeup interrupts may occur during a system sleep transition. +* Postpone handling until the PHY has resumed. +*/ +if (IS_ENABLED (CONFIG_PM_SLEEP ) && phydev->irq_suspended) { +struct net_device *netdev = phydev->attached_dev; + +if (netdev) { +struct device *parent = netdev->dev.parent; + +if (netdev->wol_enabled) +pm_system_wakeup (); +else if (device_may_wakeup (&netdev->dev)) +pm_wakeup_dev_event (&netdev->dev,0 , true); +else if (parent &&device_may_wakeup (parent)) +pm_wakeup_dev_event (parent,0 , true); + } + + phydev->irq_rerun =1 ; +disable_irq_nosync (irq); +return IRQ_HANDLED ; + } +mutex_lock (&phydev->lock); ret = drv->handle_interrupt (phydev);mutex_unlock (&phydev->lock);
drivers/net/phy/phy_device.c +23 -0
@@ -278,6 +278,15 @@ static __maybe_unused int mdio_bus_phy_suspend(struct device *dev)if (phydev->mac_managed_pm)return 0 ; +/* Wakeup interrupts may occur during the system sleep transition when +* the PHY is inaccessible. Set flag to postpone handling until the PHY +* has resumed. Wait for concurrent interrupt handler to complete. +*/ +if (phy_interrupt_is_valid (phydev)) { + phydev->irq_suspended =1 ; +synchronize_irq (phydev->irq); + } +/* We must stop the state machine manually, otherwise it stops out of * control, possibly with the phydev->lock held. Upon resume, netdev * may call phy routines that try to grab the same lock, and that may
@@ -315,6 +324,20 @@ static __maybe_unused int mdio_bus_phy_resume(struct device *dev)if (ret <0 )return ret; no_resume: +if (phy_interrupt_is_valid (phydev)) { + phydev->irq_suspended =0 ; +synchronize_irq (phydev->irq); + +/* Rerun interrupts which were postponed by phy_interrupt() +* because they occurred during the system sleep transition. +*/ +if (phydev->irq_rerun) { + phydev->irq_rerun =0 ; +enable_irq (phydev->irq); +irq_wake_thread (phydev->irq, phydev); + } + } +if (phydev->attached_dev && phydev->adjust_link)phy_start_machine (phydev);
include/linux/phy.h +6 -0
@@ -572,6 +572,10 @@ struct macsec_ops;* @mdix_ctrl: User setting of crossover * @pma_extable: Cached value of PMA/PMD Extended Abilities Register * @interrupts: Flag interrupts have been enabled +* @irq_suspended: Flag indicating PHY is suspended and therefore interrupt +* handling shall be postponed until PHY has resumed +* @irq_rerun: Flag indicating interrupts occurred while PHY was suspended, +* requiring a rerun of the interrupt handler after resume * @interface: enum phy_interface_t value * @skb: Netlink message for cable diagnostics * @nest: Netlink nest used for cable diagnostics
@@ -626,6 +630,8 @@ struct phy_device {/* Interrupts are enabled */ unsigned interrupts:1; + unsigned irq_suspended:1; + unsigned irq_rerun:1;enum phy_state state;