Selecting Fan Control Packages

[iwoloschin]

Unexpected behavior you saw
I have a system using phosphor-pid-control for fan control, when trying to run ipmitool chassis power on the system would briefly start booting, then turn off. After investigation I found that phosphor-fan-monitor@0 was starting, failing to detect fans, and shutting down the host.

Expected behavior
That phosphor-fan-presence packages are not even installed in my machine image.

To Reproduce

1. Set up a machine.conf file with PREFERRED_PROVIDER_virtual/obmc-fan-mgmt = "packagegroup-company".
2. Set up packagegroup-company.bb with:

PROVIDES += "virtual/obmc-fan-mgmt"
RPROVIDES:${PN}-fans += "virtual-obmc-fan-mgmt"
RDEPENDS:${PN}-fans = " \
        phosphor-pid-control \
        "

3. Turn off power (ipmitool chassis power off or Redfish equivalent) and turn power on (ipmitool chassis power on or Redfish equivalent).

OpenBMC Information:

• /etc/os-release: Custom, but last upstream commit is 7b7ff3f
• Any additional patches or changes: I've ported phosphor-state-manager to this platform (2P AMD Epyc) and that is not upstreamed, should not impact any of the systemd targets/services or yocto packages though.

Additional context
It seems that obmc-fan-mgmt was deprecated 6 years ago and obmc-fan-control was intended to be used instead, but there is no way to set a PREFERRED_PROVIDER_virtual/obmc-fan-control. If I am using Entity Manager & phosphor-pid-control I neither want nor need phosphor-fan-presence packages.

[williamspatrick]

@spinler Can you take a look?

[spinler]

I haven't really thought much about how phosphor-fan is pulled into an image since we enabled it back around 2017 for our systems. The majority of systems in the tree use pid-control instead of phosphor-fan, so I assume there is a straightforward way to handle this. When I can get the time I will look into it more.