tree 3d1d46cbce4af79dce189d134df9391413f4bbcb
parent c7b2be3932fd5064769c319b4581f149baf21fe8
author Patrick Rudolph <patrick.rudolph@9elements.com> 1697193614 +0200
committer Josh Lehan <krellan@google.com> 1707782778 +0000

pid/fancontroller: Set failsafe PWM in destructor

Introduce a new feature that's guarded by a new meson option
'offline-failsafe-pwm':

After the FanController object was destroyed it can no longer regulate
the fans. To prevent system failure set all fans to the FailSafePercent
defined in the configuration.

In addition to rebuilding configuration it also allows to keep the fans
in FailSafe mode as long as the phosphor-pid-control.service is stopped
or the system reboots. However this change doesn't cover the case of
a program crash where the destructor won't be executed. Abnormal program
termination must be handled by systemd and it out of scope of this
change.

Tested: 'systemctl stop phosphor-pid-control.service' and see the fans
        ramp up to FailSafePercent.

Change-Id: I81262b07fd4c1212efc1a4ba4635bde8bc7b5215
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>