[SRU][N][PATCH 0/1] No IP Address assigned after hot-plugging Ethernet cable on HP Platform

[Stefan Bader]

On 06.08.25 17:10, En-Wei Wu wrote:
> BugLink: https://bugs.launchpad.net/bugs/2115393
> 
> [ Impact ]
> 
> On HP platform, a system equipped with Intel 8086:57a0 Ethernet exhibits
> a symptom: after hot plugging the Ethernet cable, the network interface
> can't get an IP address from DHCP server. This is caused by a packet
> loss problem introduced by the commit from stable update:
> 
> 96d4a384ccc2edfe5 e1000e: change k1 configuration on MTP and later
> platforms
> 
> The packet loss problem reproduces with the 100% rate, when no packet
> can be sent and received by the Ethernet controller, eventually block
> the DCHP process.
> 
> Although there is an RFC patch [1] from upstream mailing list, it simply
> introduces a module parameter which can turn the k1 configuration off.
> That being said, turning off the k1 configuration would increase the
> system's power consumption.
> 
> [ Fix ]
> 
> For the temporary solution, we revert the following patch:
> 
> 96d4a384ccc2edfe5 e1000e: change k1 configuration on MTP and later
> platforms
> 
> [ Test Plan ]
> 
> 1. Boot into Ubuntu kernel with Ethernet cable unplugged
> 2. Plug the Ethernet cable into the machine
> 3. Check if the system can get IP address from a DHCP server
> 
> [ Where problems could occur ]
> 
> Reverting the commit might cause minor packet loss on some platform,
> said by the Intel Ethernet maintainer. That being said, we have not
> observed it on our certified machines.

Hi En-Wei,

the revert is undoing 9bcaabfe4218c0f6e65ac4364b94ff7e1b418d04 which was 
applied to fix 9bcaabfe4218c0f6e65ac4364b94ff7e1b418d04 "Latitude 5450 
is experiencing packet loss on Ethernet in Ubuntu 22.04" [Just released 
in the 2025.07.14 cycle]. Is that not a certified machine? Are we not 
creating a ping-pong effect between those 2 bug reports?

-Stefan
> 
> [ Additional Information ]
> 
> [1]
> https://lore.kernel.org/netdev/20250710092455.1742136-1-vitaly.lifshits@intel.com/
> 
> En-Wei Wu (1):
>    Revert "e1000e: change k1 configuration on MTP and later platforms"
> 
>   drivers/net/ethernet/intel/e1000e/defines.h |  3 -
>   drivers/net/ethernet/intel/e1000e/ich8lan.c | 80 ++-------------------
>   drivers/net/ethernet/intel/e1000e/ich8lan.h |  4 --
>   3 files changed, 5 insertions(+), 82 deletions(-)
> 

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