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author | Florian Fainelli <f.fainelli@gmail.com> | 2022-08-01 16:34:03 -0700 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2022-08-03 19:20:41 -0700 |
commit | 744d23c71af39c7dc77ac7c3cac87ae86a181a85 (patch) | |
tree | 71a5858c1bed8f900892bb128578622b6ae4962a /drivers/net | |
parent | 7de196a6aa3a02f6079f5bf8796df4cb6cb5e783 (diff) | |
download | linux-744d23c71af39c7dc77ac7c3cac87ae86a181a85.tar.gz linux-744d23c71af39c7dc77ac7c3cac87ae86a181a85.tar.bz2 linux-744d23c71af39c7dc77ac7c3cac87ae86a181a85.zip |
net: phy: Warn about incorrect mdio_bus_phy_resume() state
Calling mdio_bus_phy_resume() with neither the PHY state machine set to
PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication
that we can produce a race condition looking like this:
CPU0 CPU1
bcmgenet_resume
-> phy_resume
-> phy_init_hw
-> phy_start
-> phy_resume
phy_start_aneg()
mdio_bus_phy_resume
-> phy_resume
-> phy_write(..., BMCR_RESET)
-> usleep() -> phy_read()
with the phy_resume() function triggering a PHY behavior that might have
to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix
brcm_fet_config_init()") for instance) that ultimately leads to an error
reading from the PHY.
Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220801233403.258871-1-f.fainelli@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net')
-rw-r--r-- | drivers/net/phy/phy_device.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index a74b320f5b27..0c6efd792690 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -316,6 +316,12 @@ static __maybe_unused int mdio_bus_phy_resume(struct device *dev) phydev->suspended_by_mdio_bus = 0; + /* If we managed to get here with the PHY state machine in a state other + * than PHY_HALTED this is an indication that something went wrong and + * we should most likely be using MAC managed PM and we are not. + */ + WARN_ON(phydev->state != PHY_HALTED && !phydev->mac_managed_pm); + ret = phy_init_hw(phydev); if (ret < 0) return ret; |