On 1.12.2018 0:16, Heiner Kallweit wrote: > On 30.11.2018 19:45, Anssi Hannula wrote: >> When a PHY_HALTED phydev is resumed by phy_start(), it is set to >> PHY_RESUMING to wait for the link to come up. >> >> However, if the phydev was put to PHY_HALTED (by e.g. phy_stop()) before >> autonegotiation was ever started by phy_state_machine(), autonegotiation >> remains unconfigured, i.e. phy_config_aneg() is never called. >> > phy_stop() should only be called once the PHY was started. But it's > right that we don't have full control over it because misbehaving > drivers may call phy_stop() even if the PHY hasn't been started yet.
Having run phy_start() does not guarantee that the phy_state_machine() has been run at least once, though. I was able to reproduce the issue by calling phy_start(); phy_stop(). Then on the next phy_start() autoneg is not configured. > I think phy_error() and phy_stop() should be extended to set the state > to PHY_HALTED only if the PHY is in a started state, means: > don't touch the state if it's DOWN, READY, or HALTED. > In case of phy_error() it's more a precaution, because it's used within > phylib only and AFAICS it can be triggered from a started state only. This wouldn't fix the issue that occurs when phy_stop() is called right after phy_start(), though, as PHY is in UP state then. > > So yes, there is a theoretical issue. But as you wrote already, I think > there's a better way to deal with it. > > For checking whether PHY is in a started state you could use the helper > which is being discussed here: > https://marc.info/?l=linux-netdev&m=154360368104946&w=2 > > >> Fix that by going to PHY_UP instead of PHY_RESUMING if autonegotiation >> has never been configured. >> >> Signed-off-by: Anssi Hannula <anssi.hann...@bitwise.fi> >> --- >> >> This doesn't feel as clean is I'd like to, though. Maybe there is a >> better way? >> >> >> drivers/net/phy/phy.c | 11 ++++++++++- >> include/linux/phy.h | 2 ++ >> 2 files changed, 12 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c >> index d46858694db9..7a650cce7599 100644 >> --- a/drivers/net/phy/phy.c >> +++ b/drivers/net/phy/phy.c >> @@ -553,6 +553,8 @@ int phy_start_aneg(struct phy_device *phydev) >> if (err < 0) >> goto out_unlock; >> >> + phydev->autoneg_configured = 1; >> + >> if (phydev->state != PHY_HALTED) { >> if (AUTONEG_ENABLE == phydev->autoneg) { >> err = phy_check_link_status(phydev); >> @@ -893,7 +895,14 @@ void phy_start(struct phy_device *phydev) >> break; >> } >> >> - phydev->state = PHY_RESUMING; >> + /* if autoneg/forcing was never configured, go back to PHY_UP >> + * to make that happen >> + */ >> + if (!phydev->autoneg_configured) >> + phydev->state = PHY_UP; >> + else >> + phydev->state = PHY_RESUMING; >> + >> break; >> default: >> break; >> diff --git a/include/linux/phy.h b/include/linux/phy.h >> index 8f927246acdb..b306d5ed9d09 100644 >> --- a/include/linux/phy.h >> +++ b/include/linux/phy.h >> @@ -389,6 +389,8 @@ struct phy_device { >> unsigned loopback_enabled:1; >> >> unsigned autoneg:1; >> + /* autoneg has been configured at least once */ >> + unsigned autoneg_configured:1; >> /* The most recently read link state */ >> unsigned link:1; >> >> -- Anssi Hannula / Bitwise Oy
