Re: [PATCH iwl-net v3] e1000e: restore jumbo config after DMoff exit

["Kadosh, MoriyaX" <moriyax.kadosh@intel.com>]

On 29/09/2026 10:05, Loktionov, Aleksandr wrote:
> 
> 
>> -----Original Message-----
>> From: Craig I. Hagan <hagan@amazon.com>
>> Sent: Monday, September 28, 2026 11:06 PM
>> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
>> Przemyslaw <przemyslaw.kitszel@intel.com>
>> Cc: Andrew Lunn <andrew+netdev@lunn.ch>; David S . Miller
>> <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub
>> Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; intel-
>> wired-lan@lists.osuosl.org; netdev@vger.kernel.org; linux-
>> kernel@vger.kernel.org; stable@vger.kernel.org; Fabio Sabai
>> <sabfabio@amazon.com>; Matt Vollrath <tactii@gmail.com>
>> Subject: [PATCH iwl-net v3] e1000e: restore jumbo config after DMoff
>> exit
>>
>> On an I219 (pch_spt+) at jumbo MTU, after a link partner reset (e.g. a
>> switch reboot) the interface can come back up unable to pass traffic
>> until it is manually reset. Observed on I219-LM (8086:15b7) at MTU
>> 9000.
>>
>> When the MAC exits the DMoff state on link-up, the watchdog resets
>> only the PHY. A bare PHY reset does not re-run the jumbo-frame
>> workaround (e1000_lv_jumbo_workaround_ich8lan), so the jumbo
>> configuration is left unapplied and traffic stalls. This was seen with
>> NIC runtime PM disabled; if runtime PM were enabled, the device should
>> go through a full reset on resume, avoiding this issue.
>>
>> Request a full reset (FLAG_RESTART_NOW) instead of the bare PHY reset
>> when the MAC exits DMoff, so the normal reset path re-applies the
>> jumbo-frame configuration.
>>
>> Fixes: def4ec6dce39 ("e1000e: PCIm function state support")
>> Cc: stable@vger.kernel.org
>> Reported-by: Fabio Sabai <sabfabio@amazon.com>
>> Closes: https://github.com/systemd/systemd/issues/25925
>> Suggested-by: Matt Vollrath <tactii@gmail.com>
>> Reviewed-by: Matt Vollrath <tactii@gmail.com>
>> Tested-by: Matt Vollrath <tactii@gmail.com>
>> Assisted-by: LLM
>> Signed-off-by: Craig I. Hagan <hagan@amazon.com>
>> ---
>> v3: Correct the Fixes: tag to def4ec6dce39 ("e1000e: PCIm function
>>      state support"), which introduced the DMoff-exit bare PHY reset;
>>      2e7256f12cdb only added a pre-condition. This lets stable reach
>>      the affected trees (v5.3+, including 5.4/5.10). Add Reviewed-by/
>>      Tested-by from Matt Vollrath.
>> v2: Rework per review: request a full reset on DMoff exit so the
>>      jumbo-frame workaround is re-applied (root cause identified by
>>      Matt Vollrath); drop the diagnostic e_info. v1:
>>      https://lore.kernel.org/netdev/20260923235832.473-1-
>> hagan@amazon.com/
>>
>>   drivers/net/ethernet/intel/e1000e/netdev.c | 8 +++++---
>>   1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
>> b/drivers/net/ethernet/intel/e1000e/netdev.c
>> index 844f31ab3..df7da86a8 100644
>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>> @@ -5264,9 +5264,11 @@ static void e1000_watchdog_task(struct
>> work_struct *work)
>>   					usleep_range(10000, 20000);
>>   					pcim_state = er32(STATUS);
>>
>> -					/* Checking if MAC exited DMoff
>> state */
>> -					if (!(pcim_state &
>> E1000_STATUS_PCIM_STATE))
>> -						e1000_phy_hw_reset(&adapter-
>>> hw);
>> +					/* MAC exited DMoff; do a full
>> reset. */
>> +					if (!(pcim_state &
>> E1000_STATUS_PCIM_STATE)) {
>> +						adapter->flags |=
>> FLAG_RESTART_NOW;
>> +						goto link_up;
>> +					}
>>   				}
>>   			}
>>
>> --
>> 2.47.3
> 
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Moriya Kadosh <moriyax.kadosh@intel.com>