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

[En-Wei Wu]

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.

[ 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(-)

-- 
2.43.0