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 <stable@xxxxxxxxxxxxxxx> know about it.
>From 6aae7a6232c6444941de8e5a1e0cc42442ab9bce Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Date: Tue, 12 Dec 2017 10:45:36 +0000
Subject: [PATCH] net: phy: fix resume handling
From: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
[ 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 <rmk+kernel@xxxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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(-)
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -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;
}
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -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);
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -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 rmk+kernel@xxxxxxxxxxxxxxx are
queue-4.14/net-phy-fix-resume-handling.patch