Thread (6 messages) 6 messages, 3 authors, 2015-06-28

Re: [net PATCH 1/1] net: phy: fix phy link up when limiting speed via device tree

From: Florian Fainelli <f.fainelli@gmail.com>
Date: 2015-06-25 17:32:33

2015-06-25 9:51 GMT-07:00 Mugunthan V N [off-list ref]:
When limiting phy link speed using "max-speed" to 100mbps or less on a
giga bit phy, phy never completes auto negotiation and phy state
machine is held in PHY_AN. Fixing this issue by comparing the giga
bit advertise though phydev->supported doesn't have it but phy has
BMSR_ESTATEN set. So that auto negotiation is restarted as old and
new advertise are different and link comes up fine.
This looks valid, however, I am curious why this part of the code:

        oldadv = adv;
        adv &= ~(ADVERTISE_ALL | ADVERTISE_100BASE4 | ADVERTISE_PAUSE_CAP |
                 ADVERTISE_PAUSE_ASYM);
        adv |= ethtool_adv_to_mii_adv_t(advertise);

        if (adv != oldadv) {
                err = phy_write(phydev, MII_ADVERTISE, adv);

                if (err < 0)
                        return err;
                changed = 1;
        }

Is not flagging this as a change already?
quoted hunk ↗ jump to hunk
Signed-off-by: Mugunthan V N <redacted>
---
 drivers/net/phy/phy_device.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index bdfe51f..d551df6 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -796,10 +796,11 @@ static int genphy_config_advert(struct phy_device *phydev)
        if (phydev->supported & (SUPPORTED_1000baseT_Half |
                                 SUPPORTED_1000baseT_Full)) {
                adv |= ethtool_adv_to_mii_ctrl1000_t(advertise);
-               if (adv != oldadv)
-                       changed = 1;
        }

+       if (adv != oldadv)
+               changed = 1;
+
        err = phy_write(phydev, MII_CTRL1000, adv);
        if (err < 0)
                return err;
--
2.4.4.409.g5b1d901


-- 
Florian
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