Re: [PATCH v6 2/7] iwlwifi: mei: add the driver to allow cooperation with CSME

Emmanuel Grumbach [off-list ref] writes:

On Wed, Nov 10, 2021 at 11:40 AM Kalle Valo [off-list ref] wrote:

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Emmanuel Grumbach [off-list ref] writes:

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So if I'm understanding correctly, enabling CONFIG_IWLMEI will break
existing iwlwifi setups? Or am I missing something?

Ok, I'll share more details.
The coexistence between iwlwifi and CSME has never really been taken care
of. CSME is a feature meant for enterprise and those systems typically run
Windows which is why the Windows driver has had this feature for years
but not Linux.
iwlmei will not do anything if you don't have CSME configured to use the
WLAN device. Someone needs to actively configure CSME to use WLAN for
this to happen. Very few systems have this configuration.

So in a case when CSME/AMT WLAN (or whatever the feature under
discussion is called) is disabled in the BIOS and CONFIG_IWLMEI is
enabled in the kernel build, iwlwifi will work as before? This is the
most important part for me, we must not break people's network access
when they upgrade the kernel.

Yes.

Very good, this is most important for me.

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The only way to prevent this situation would be to know what device
the user has from iwlmei in the mei bus enumeration but this is
unfortunately not possible.

I hope that made things clearer. I know all this is confusing, many
pieces of details that I hoped I wouldn't have to bore you with :)

It would have been a lot easier and faster to mention all this in the
commit logs from the beginning. Dumping me patches without commit logs
and no clear explanation is not really building confidence for me.

I understand. There are loads of details and I didn't really want to bother you
with all of them, I guess I now know that you are the type of person who want
the details and I'll be clearer the next time.

It's really comes down to trusting the patches, if I don't even
understand what the patches do I will have a hard time trusting them.

Practically speaking, I owe you a v8 with the WARNING I mentioned plus
the bugfix I talked about.

Do you want it now or you want me to wait for more comments?

I'm not planning to review v7 anymore, so please do submit v8.

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