Re: [Intel-wired-lan] [PATCH 2/3] e1000e: Make mei_me active when e1000e is in use

On Wed, Jul 14, 2021 at 5:06 PM Ruinskiy, Dima [off-list ref] wrote:

On 14/07/2021 9:28, Kai-Heng Feng wrote:

quoted

quoted

I do not know how MEI driver affect 1Gbe driver - so, I would suggest to
involve our CSME engineer (alexander.usyskin@intel.com) and try to
investigate this problem.
Does this problem observed on Dell systems? As I heard no reproduction
on Intel's RVP platform.
Another question: does disable mei_me runpm solve your problem?

Yes, disabling runpm on mei_me can workaround the issue, and that's
essentially what this patch does by adding DL_FLAG_PM_RUNTIME |
DL_FLAG_RPM_ACTIVE flag.

Kai-Heng

Hi, Kai-Heng,

If the goal of the patch is to essentially disable runpm on mei_me, then
why is the patch touching code in the e1000e driver?

We can put the workaround in e1000e, mei_me or as PCI quirk.
But since the bug itself manifests in e1000e, I think it's more
appropriate to put it here.

To be more specific, it doesn't disable runtime suspend on mei_me, it
makes mei_me the power supplier of e1000e.
So when e1000e can be runtime suspended (i.e. no link partner), mei_me
can also get runtime suspended too.

I agree with Sasha Neftin; it seems like the wrong location, and the
wrong way to do it, even if it currently works. We need to understand
what causes runpm of mei_me to adversely affect LAN Rx, and for this we
need the involvement of mei_me owners.

I think it's the right location, however I totally agree with your
other arguments.
There are many users already affected by this bug, so if a proper fix
isn't available for now, the temporary workaround can help here.

Kai-Heng

--Dima
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