On 12/01/2017 14:05, Mason wrote: > I'm wondering what are the semantics of calling > > ip link set dev eth0 down > > I was expecting that to somehow instruct the device's ethernet driver > to shut everything down, have the PHY tell the peer that it's going > away, maybe even put the PHY in some low-power mode, etc. > > But it doesn't seem to be doing any of that on my HW. > > So what exactly is it supposed to do? > > > And on top of that, I am seeing random occurrences of > > nb8800 26000.ethernet eth0: Link is Down > > Sometimes it is printed immediately. > Sometimes it is printed as soon as I run "ip link set dev eth0 up" (?!) > Sometimes it is not printed at all. > > I find this erratic behavior very confusing. > > Is it the symptom of some deeper bug?
Here's an example of "Link is Down" printed when I set link up: At [ 62.750220] I run ip link set dev eth0 down Then leave the system idle for 10 minutes. At [ 646.263041] I run ip link set dev eth0 up At [ 647.364079] it prints "Link is Down" At [ 649.417434] it prints "Link is Up - 1Gbps/Full - flow control rx/tx" I think whether I set up the PHY to use interrupts or polling does have an influence on the weirdness I observe. AFAICT, changing the interface flags is done in dev_change_flags which calls __dev_change_flags and __dev_notify_flags Is one of these supposed to call the device driver through a callback at some point? How/when is the phy_state_machine notified of the change in interface flags? Regards.
