Re: [PATCH RESEND] iwlwifi, Do not implement thermal zone unless ucode is loaded

From: Prarit Bhargava
Date: Wed Jul 13 2016 - 06:01:49 EST

On 07/13/2016 02:50 AM, Kalle Valo wrote:
> Prarit Bhargava <prarit@xxxxxxxxxx> writes:
>>> We implement thermal zone because we do support it, but the problem is
>>> that we need the firmware to be loaded for that. So you can argue that
>>> we should register *later* when the firmware is loaded. But this is
>>> really not helping all that much because the firmware can also be
>>> stopped at any time. So you'd want us to register / unregister the
>>> thermal zone anytime the firmware is loaded / unloaded?
>> You might have to do that. I think that if the firmware enables a feature then
>> the act of loading the firmware should run the code that enables the feature.
>> IMO of course.
> But I suspect that the iwlwifi firmware is loaded during interface up
> (and unloaded during interface down) and in that case
> register/unregister would be happening all the time.

You make it sound like the interface is coming and going a 1000 times a second.
Maybe this happens once during runtime & during suspend/resume cycles? What
about the cases when the firmware isn't present (and that's what lead me to this

That doesn't sound
> like a good idea. I would rather try to fix the thermal interface to
> handle the cases when the measurement is not available.

Userspace is broken because of this change. I've had to make another horrible
change to cpufreq for a similar change so I don't see the argument here to just
blame userspace and ignore the outcome of the patch.