On Tue, Oct 17, 2023 at 09:03:01PM +0800, Jijie Shao wrote: > > on 2023/7/31 17:10, Jijie Shao wrote: > > > > on 2023/7/30 2:23, Andrew Lunn wrote: > > > > Now i wounder if you are fixing the wrong thing. Maybe you > > > > should be > > > > fixing the PHY so it does not report up and then down? You > > > > say 'very > > > > snall intervals', which should in fact be 1 second. So is the PHY > > > > reporting link for a number of poll intervals? 1min to 10 minutes? > > > > > > > > Andrew > > > > > > > > Yes, according to the log records, the phy polls every second, > > > > but the link status changes take time. > > > > Generally, it takes 10 seconds for the phy to detect link down, > > > > but occasionally it takes several minutes to detect link down, > > > What PHY driver is this? > > > > > > It is not so clear what should actually happen with auto-neg turned > > > off. With it on, and the link going down, the PHY should react after > > > about 1 second. It is not supposed to react faster than that, although > > > some PHYs allow fast link down notification to be configured. > > > > > > Have you checked 802.3 to see what it says about auto-neg off and link > > > down detection? > > > > > > I personally would not suppress this behaviour in the MAC > > > driver. Otherwise you are going to have funny combinations of special > > > cases of a feature which very few people actually use, making your > > > maintenance costs higher. > > > > > > Andrew > > Hi Andrew, > We've rewritten the commit log to explain this problem, > Would you please take some time to review that? > > The following is the new commit log: > This patch is to correct a wrong log info "link down/up" in hns3 driver. > When setting autoneg off without changing speed and duplex, the link > should be not changed. However in hns3 driver, it print link down/up once > incorrectly. We trace the phy machine state and find the phy change form > PHY_UP to PHY_RUNNING. No other state of PHY occurs during this process. > MDIO trace also indicate the link is on. The wrong log info and mdio > trace are showed as followed: > > [ 843.720783][ T367] hns3 0000:35:00.0 eth1: set link(phy): autoneg=0, > speed=10, duplex=1 > [ 843.736087][ T367] hns3 0000:35:00.0 eth1: link down > [ 843.773506][ T17] RTL8211F Gigabit Ethernet mii-0000:35:00.0:02: PHY > state change UP -> RUNNING > [ 844.674668][ T31] hns3 0000:35:00.0 eth1: link up I still think this is totally valid and correct. When you turn auto-neg off the link partner is going to react to that, it might drop the link. After a while, the link partner will give up trying to perform auto-neg and might fall back to 10/Half. At which point, the link might allow traffic flow. However, in this example, you have a duplex mis-match, so it might not work correctly. Turning off auto-neg is something you need to do at both ends, and you need to then force both ends to the same settings. Link down is expected. I would actually be suppressed if no link down events were reported. Andrew
