Patch "[PATCH] net: phy: fix resume handling" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Mar 16, 2018

Subsystems (3)

Network drivers Stable branch Ethernet PHY

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2018-03-16 12:38 UTC #0 lore raw

This is a note to let you know that I've just added the patch titled

[PATCH] net: phy: fix resume handling

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-phy-fix-resume-handling.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 6aae7a6232c6444941de8e5a1e0cc42442ab9bce Mon Sep 17 00:00:00 2001

From: Russell King <[email protected]>
Date: Tue, 12 Dec 2017 10:45:36 +0000
Subject: [PATCH] net: phy: fix resume handling

From: Russell King <[email protected]>

[ Upstream commit f5e64032a799d4f54decc7eb6aafcdffb67f9ad9 ]

When a PHY has the BMCR_PDOWN bit set, it may decide to ignore writes to other registers, or reset the registers to power-on defaults. Micrel PHYs do this for their interrupt registers.

The current structure of phylib tries to enable interrupts before resuming (and releasing) the BMCR_PDOWN bit. This fails, causing Micrel PHYs to stop working after a suspend/resume sequence if they are using interrupts.

Fix this by ensuring that the PHY driver resume methods do not take the phydev->lock mutex themselves, but the callers of phy_resume() take that lock. This then allows us to move the call to phy_resume() before we enable interrupts in phy_start().

Signed-off-by Russell King <[email protected]>

Reviewed-by Andrew Lunn <[email protected]>

Signed-off-by David S. Miller <[email protected]>

Signed-off-by Sasha Levin <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 drivers/net/phy/at803x.c     |    4 ----
 drivers/net/phy/phy.c        |    9 +++------
 drivers/net/phy/phy_device.c |   10 ++++++----
 3 files changed, 9 insertions(+), 14 deletions(-)

drivers/net/phy/at803x.c +0 -4

@@ -239,14 +239,10 @@ static int at803x_resume(struct phy_devi
 {
 	int value;
 
-	mutex_lock(&phydev->lock);
-
 	value = phy_read(phydev, MII_BMCR);
 	value &= ~(BMCR_PDOWN | BMCR_ISOLATE);
 	phy_write(phydev, MII_BMCR, value);
 
-	mutex_unlock(&phydev->lock);
-
 	return 0;
 }

drivers/net/phy/phy.c +3 -6

@@ -828,7 +828,6 @@ EXPORT_SYMBOL(phy_stop);
  */
 void phy_start(struct phy_device *phydev)
 {
-	bool do_resume = false;
 	int err = 0;
 
 	mutex_lock(&phydev->lock);

@@ -841,6 +840,9 @@ void phy_start(struct phy_device *phydev
 		phydev->state = PHY_UP;
 		break;
 	case PHY_HALTED:
+		/* if phy was suspended, bring the physical link up again */
+		phy_resume(phydev);
+
 		/* make sure interrupts are re-enabled for the PHY */
 		if (phy_interrupt_is_valid(phydev)) {
 			err = phy_enable_interrupts(phydev);

@@ -849,17 +851,12 @@ void phy_start(struct phy_device *phydev
 		}
 
 		phydev->state = PHY_RESUMING;
-		do_resume = true;
 		break;
 	default:
 		break;
 	}
 	mutex_unlock(&phydev->lock);
 
-	/* if phy was suspended, bring the physical link up again */
-	if (do_resume)
-		phy_resume(phydev);
-
 	phy_trigger_machine(phydev, true);
 }
 EXPORT_SYMBOL(phy_start);

drivers/net/phy/phy_device.c +6 -4

@@ -135,7 +135,9 @@ static int mdio_bus_phy_resume(struct de
 	if (!mdio_bus_phy_may_suspend(phydev))
 		goto no_resume;
 
+	mutex_lock(&phydev->lock);
 	ret = phy_resume(phydev);
+	mutex_unlock(&phydev->lock);
 	if (ret < 0)
 		return ret;

@@ -1026,7 +1028,9 @@ int phy_attach_direct(struct net_device
 	if (err)
 		goto error;
 
+	mutex_lock(&phydev->lock);
 	phy_resume(phydev);
+	mutex_unlock(&phydev->lock);
 	phy_led_triggers_register(phydev);
 
 	return err;

@@ -1157,6 +1161,8 @@ int phy_resume(struct phy_device *phydev
 	struct phy_driver *phydrv = to_phy_driver(phydev->mdio.dev.driver);
 	int ret = 0;
 
+	WARN_ON(!mutex_is_locked(&phydev->lock));
+
 	if (phydev->drv && phydrv->resume)
 		ret = phydrv->resume(phydev);

@@ -1639,13 +1645,9 @@ int genphy_resume(struct phy_device *phy
 {
 	int value;
 
-	mutex_lock(&phydev->lock);
-
 	value = phy_read(phydev, MII_BMCR);
 	phy_write(phydev, MII_BMCR, value & ~BMCR_PDOWN);
 
-	mutex_unlock(&phydev->lock);
-
 	return 0;
 }
 EXPORT_SYMBOL(genphy_resume);

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/net-phy-fix-resume-handling.patch