Messages in this thread | | | Date | Thu, 9 May 2024 15:46:42 +0200 | From | Andrew Lunn <> | Subject | Re: [Intel-wired-lan] [PATCH v2 2/2] e1000e: fix link fluctuations problem |
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On Thu, May 09, 2024 at 12:13:27PM +0300, Ruinskiy, Dima wrote: > On 08/05/2024 8:05, Sasha Neftin wrote: > > On 07/05/2024 15:31, Andrew Lunn wrote: > > > On Fri, May 03, 2024 at 06:18:36PM +0800, Ricky Wu wrote: > > > > As described in https://bugzilla.kernel.org/show_bug.cgi?id=218642, > > > > Intel I219-LM reports link up -> link down -> link up after hot-plugging > > > > the Ethernet cable. > > > > > > Please could you quote some parts of 802.3 which state this is a > > > problem. How is this breaking the standard. > > > > > > Andrew > > > > In I219-* parts used LSI PHY. This PHY is compliant with the 802.3 IEEE > > standard if I recall correctly. Auto-negotiation and link establishment > > are processed following the IEEE standard and could vary from platform > > to platform but are not violent to the IEEE standard. > > > > En-Wei, My recommendation is not to accept these patches. If you think > > there is a HW/PHY problem - open a ticket on Intel PAE. > > > > Sasha > > I concur. I am wary of changing the behavior of some driver fundamentals, to > satisfy a particular validation/certification flow, if there is no real > functionality problem. It can open a big Pandora box. > > Checking the Bugzilla report again, I am not sure we understand the issue > fully: > > [ 143.141006] e1000e 0000:00:1f.6 enp0s31f6: NIC Link is Up 1000 Mbps Half > Duplex, Flow Control: None > [ 143.144878] e1000e 0000:00:1f.6 enp0s31f6: NIC Link is Down > [ 146.838980] e1000e 0000:00:1f.6 enp0s31f6: NIC Link is Up 1000 Mbps Full > Duplex, Flow Control: None > > This looks like a very quick link "flap", following by proper link > establishment ~3.7 seconds later. These ~3.7 seconds are in line of what > link auto-negotiation would take (auto-negotiation is the default mode for > this driver).
That actually seems slow. It is normally a little over 1 second. I forget the exact number. But is the PHY being polled once a second, rather than being interrupt driven?
> The first print (1000 Mbps Half Duplex) actually makes no > sense - it cannot be real link status since 1000/Half is not a supported > speed.
It would be interesting to see what the link partner sees. What does it think the I219-LM is advertising? Is it advertising 1000BaseT_Half? But why would auto-neg resolve to that if 1000BaseT_Full is available?
> So it seems to me that actually the first "link up" is an > incorrect/incomplete/premature reading, not the "link down".
Agreed. Root cause this, which looks like a real problem, rather than apply a band-aid for a test system.
Andrew
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