Re: [PATCH net 5/6] net: hns3: fix wrong print link down up

[Jijie Shao]

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

     kworker/1:1-32      [001] ....   841.457231: mdio_access: mii-0000:
35:00.0 read  phy:0x02 reg:0x01 val:0x79ad
     kworker/1:1-32      [001] ....   842.486496: mdio_access: mii-0000:
35:00.0 read  phy:0x02 reg:0x01 val:0x79ad
     kworker/1:1-32      [001] ....   843.520565: mdio_access: mii-0000:
35:00.0 read  phy:0x02 reg:0x01 val:0x79ad
     kworker/0:1-17      [000] ....   843.757147: mdio_access: mii-0000:
35:00.0 read  phy:0x02 reg:0x01 val:0x798d
     kworker/0:1-17      [000] ....   844.799141: mdio_access: mii-0000:
35:00.0 read  phy:0x02 reg:0x01 val:0x798d
     kworker/0:1-17      [000] ....   845.831513: mdio_access: mii-0000:
35:00.0 read  phy:0x02 reg:0x01 val:0x798d
     kworker/0:1-17      [000] ....   846.863053: mdio_access: mii-0000:
35:00.0 read  phy:0x02 reg:0x01 val:0x798d

Regards
Jijie