aq(4): arm PHY thermal shutdown from the admin poll

[nick_spun.io]

Summary

move thermal shutdown arming to the admin poll

this gives a more reasonable delay prior to the first attempt, and also
allows us to retry and make the option runtime-tuneable via a new
disable_thermal_arm sysctl

[emaste]

As a general rule I prefer positive-sense controls - so e.g. "enable_thermal_limit" or "thermal_limit.enable" (if we're also going to have a "thermal_limit.count or such), and it can default to true.

share/man/man4/aq.4

177

At first I read this as the driver applies the setting, which restores the firmware's own default -- it's the reset of the adapter which restored the firmware's own default, and we're overriding that, right? For the purpose of the user-facing man page I think we could just leave the note about firmware defaults out.

[nick_spun.io]

In D59593#1367454, @emaste wrote:

As a general rule I prefer positive-sense controls - so e.g. "enable_thermal_limit" or "thermal_limit.enable" (if we're also going to have a "thermal_limit.count or such), and it can default to true.

Can do - the A1 cards disable it by default and the A2 cards enable it by default so we're overriding one of them either way

[nick_spun.io]

invert knob and add parent thermal node, clean up verbiage in man page