Re: [Intel-wired-lan] [PATCH iwl-next v1 1/1] e1000e: Introduce private flag to disable K1

["Lifshits, Vitaly" <vitaly.lifshits@intel.com>]

On 8/19/2025 8:10 PM, Timo Teras wrote:
> On Tue, 19 Aug 2025 15:43:26 +0300
> Vitaly Lifshits <vitaly.lifshits@intel.com> wrote:
> 
>> The K1 state reduces power consumption on ICH family network
>> controllers during idle periods, similarly to L1 state on PCI Express
>> NICs. Therefore, it is recommended and enabled by default.
>> However, on some systems it has been observed to have adverse side
>> effects, such as packet loss. It has been established through debug
>> that the problem may be due to firmware misconfiguration of specific
>> systems, interoperability with certain link partners, or marginal
>> electrical conditions of specific units.
>>
>> These problems typically cannot be fixed in the field, and generic
>> workarounds to resolve the side effects on all systems, while keeping
>> K1 enabled, were found infeasible.
>> Therefore, add the option for users to globally disable K1 idle state
>> on the adapter.
> 
> Thanks for adding this!
> 
> However, as a user, I find it inconvenient if the default setting
> results in a subtly broken system on a device I just from a store.
> 
> Since this affects devices from multiple large vendors, would it be
> possible to add some kind of quirk mechanism to automatically enable
> this on known "bad" systems. Perhaps something based on the DMI or other
> system specific information. Could something like this be implemented?
> 
> At least in my use case I have multiple e1000e using laptops on the
> same link partner working, and only one broken device for which I
> reported this issue. So at least on my experience the issue relates to
> specific system primarily (perhaps also requiring a specific link
> partner for the issue to show up).
> 
> Thanks!

Hi Timo,

Unfortunately, there is no visible configuration that allows the driver 
to reliably identify problematic systems.
If in the future we find such data, then we can improve the workaround 
and make it automatic.

At present, the user-controlled interface is the best we have.