Messages in this thread | | | Date | Fri, 10 May 2024 12:55:54 +0300 | Subject | Re: [Intel-wired-lan] [PATCH v2 2/2] e1000e: fix link fluctuations problem | From | Sasha Neftin <> |
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On 09/05/2024 16:46, Andrew Lunn wrote: > 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?
i219 parts come with LSI PHY. 1000BASE-T half-duplex is not supported. 1000BASET half-duplex not advertised in IEEE 1000BASE-T Control Register 9.
> 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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