netdev - Re: [Intel-wired-lan] [PATCH 2/3] e1000e: Make mei

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Date:   Sun, 18 Jul 2021 11:37:45 +0300
From:   Sasha Neftin <sasha.neftin@...el.com>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>,
        "Ruinskiy, Dima" <dima.ruinskiy@...el.com>,
        <alexander.usyskin@...el.com>
CC:     Jesse Brandeburg <jesse.brandeburg@...el.com>,
        "Nguyen, Anthony L" <anthony.l.nguyen@...el.com>,
        "open list:NETWORKING DRIVERS" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        "AceLan Kao" <acelan.kao@...onical.com>,
        Jakub Kicinski <kuba@...nel.org>,
        "moderated list:INTEL ETHERNET DRIVERS" 
        <intel-wired-lan@...ts.osuosl.org>,
        "David S. Miller" <davem@...emloft.net>,
        <devora.fuxbrumer@...el.com>, <alexander.usyskin@...el.com>,
        "Edri, Michael" <michael.edri@...el.com>
Subject: Re: [Intel-wired-lan] [PATCH 2/3] e1000e: Make mei_me active when
 e1000e is in use

On 7/14/2021 12:52, Kai-Heng Feng wrote:
> On Wed, Jul 14, 2021 at 5:06 PM Ruinskiy, Dima <dima.ruinskiy@...el.com> wrote:
>>
>> On 14/07/2021 9:28, Kai-Heng Feng wrote:
>>>> I do not know how MEI driver affect 1Gbe driver - so, I would suggest to
>>>> involve our CSME engineer (alexander.usyskin@...el.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.
Hello Kai-Heng,
The temporary workaround without root cause is vague. Please, let's work 
with the manageability FW engineer (alexander.usyskin@...el.com) and 
understand the root cause.
Also, here is interfere with runpm flow of CSME - we must their inputs.
sasha
> 
> Kai-Heng
> 
>>
>> --Dima
>> ---------------------------------------------------------------------
>> Intel Israel (74) Limited
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