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authorFlorian Fainelli <f.fainelli@gmail.com>2022-08-01 16:34:03 -0700
committerJakub Kicinski <kuba@kernel.org>2022-08-03 19:20:41 -0700
commit744d23c71af39c7dc77ac7c3cac87ae86a181a85 (patch)
tree71a5858c1bed8f900892bb128578622b6ae4962a /drivers/net
parent7de196a6aa3a02f6079f5bf8796df4cb6cb5e783 (diff)
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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.c6
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;