tree 86716d288e0494309a5a05203449f5b9fc0e52ae
parent 8ee45fed31a26706484aa264e651af1d50a47ccc
author Matt Spinler <spinler@us.ibm.com> 1614635760 -0600
committer Matthew Barth <msbarth@linux.ibm.com> 1614788887 +0000

monitor: Allow missing D-Bus sensors on startup

Now that phosphor-fan-monitor is starting at the multi-user target, it
may be starting before the fan sensor hwmon daemon is able to put the
tach reading sensors on D-Bus.  This was causing the TachSensor class
objects to not get created so even if the hwmon tach sensor values did
show up later on D-Bus fan monitor wouldn't notice them.

To fix this, still create the TachSensor objects if the corresponding
hwmon D-Bus objects aren't there, and still set them to functional in
the inventory so that any other monitoring code, such as
phosphor-dbus-monitor, won't shut down the system before the hwmon tach
sensors get a chance to show up on D-Bus, which was happening on
witherspoon when a reboot was done with the power on.

When the monitor delay timer expires to kick off monitoring, a D-Bus
read is forced, and if the hwmon sensors still aren't on D-Bus then the
corresponding TachSensor objects will be set to nonfunctional to start
down the error paths.

Also, when the power state changes to on, instead of blindly setting all
TachSensor objects to functional, again check if their hwmon sensor
values are on D-Bus before doing so.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I3e62727296630bf68602b0472328f4613e1a78e3