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gerrit.openbmc.org / openbmc / phosphor-power / e97fc13a6f3253327b60120bd56c571efa29c2d0
commite97fc13a6f3253327b60120bd56c571efa29c2d0[log] [tgz]
authorShawn McCarney <shawnmm@us.ibm.com>Tue Sep 14 12:12:36 2021 -0500
committerShawn McCarney <shawnmm@us.ibm.com>Tue Sep 14 20:32:56 2021 +0000
tree050c706ba57986c93f1606314e969147ad921838
parentc8cbeac2cada1032ba5f585956f818d671cbcc65 [diff]
regulators: Fix race condition in monitor disable

There is a systemd service file that disables regulator monitoring when
the chassis is powered off.  This is necessary because we do not want to
read sensor values or check for phase faults when the chassis is powered
off.  Monitoring needs to stop before the regulators are disabled/turned
off.

The service file currently does not specify a 'Type', which means that
it defaults to Type 'simple'.  Service files of this Type are considered
started when they fork the specified executable.  That is, systemd does
not wait for the executable to complete.

In this case, we need the executable to complete.  The service runs the
regsctl executable, which makes a D-Bus method call to the regulators
application disabling monitoring.  We need this D-Bus method to complete
before proceeding with the power off.

Otherwise there is a race condition between the following:
* The timers that initiate sensor and phase fault monitoring could
  expire, causing unwanted monitoring to occur during power off.
* The regsctl executable could complete the D-Bus call, stopping
  monitoring and the associated timers.

The solution is to set the Type of the service file to 'oneshot'.  This
causes systemd to wait until the executable completes.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I399a2a4ba7f1a256c42a7e9b8b036abd1b077033
1 file changed
tree: 050c706ba57986c93f1606314e969147ad921838
  1. cold-redundancy/
  2. example/
  3. org/
  4. phosphor-power-sequencer/
  5. phosphor-power-supply/
  6. phosphor-regulators/
  7. power-sequencer/
  8. power-supply/
  9. services/
  10. test/
  11. tools/
  12. .clang-format
  13. .gitignore
  14. .shellcheck
  15. argument.hpp
  16. device.hpp
  17. device_monitor.hpp
  18. elog-errors.hpp
  19. file_descriptor.hpp
  20. gpio.cpp
  21. gpio.hpp
  22. LICENSE
  23. MAINTAINERS
  24. meson.build
  25. meson_options.txt
  26. names_values.hpp
  27. pmbus.cpp
  28. pmbus.hpp
  29. README.md
  30. types.hpp
  31. utility.cpp
  32. utility.hpp
README.md

Overview

This repository contains applications for configuring and monitoring devices that deliver power to the system.

  • cold-redundancy: Application that makes power supplies work in Cold Redundancy mode and rotates them at intervals.
  • phosphor-power-sequencer: Applications for configuring and monitoring power sequencer and related devices that support JSON-driven configuration.
  • phosphor-power-supply: Next generation power supply monitoring application.
  • phosphor-regulators: JSON-driven application that configures and monitors voltage regulators.
  • power-sequencer: A power sequencer monitoring application.
  • power-supply: Original power supply monitoring application.
  • tools/power-utils: Power supply utilities.

Build

To build all applications in this repository:

  meson build
  ninja -C build

To clean the repository and remove all build output:

  rm -rf build

You can specify meson options to customize the build process. For example, you can specify:

  • Which applications to build and install.
  • Application-specific configuration data, such as power sequencer type.
  • Whether to build tests.

Power Supply Monitor and Util JSON config

Several applications in this repository require a PSU JSON config to run. The JSON config file provides information for:

  • Where to access the pmbus attributes
  • Which attribute file in pmbus maps to which property and interface in D-Bus
  • Which kernel device directory is used on which PSU

There is an example psu.json to describe the necessary configurations.

  • inventoryPMBusAccessType defines the pmbus access type, which tells the service which sysfs type to use to read the attributes. The possible values are:
    • Base: The base dir, e.g. /sys/bus/i2c/devices/3-0069/
    • Hwmon: The hwmon dir, e.g. /sys/bus/i2c/devices/3-0069/hwmon/hwmonX/
    • Debug: The pmbus debug dir, e.g. /sys/kernel/debug/pmbus/hwmonX/
    • DeviceDebug: The device debug dir, e.g. '/sys/kernel/debug/./`
    • HwmonDeviceDebug: The hwmon device debug dir, e.g. /sys/kernel/debug/pmbus/hwmonX/cffps1/
  • fruConfigs defines the mapping between the attribute file and the FRU inventory interface and property. The configuration example below indicates that the service will read part_number attribute file from a directory specified by the above pmbus access type, and assign to PartNumber property in xyz.openbmc_project.Inventory.Decorator.Asset interface.
      "fruConfigs": [
    {
      "propertyName": "PartNumber",
      "fileName": "part_number",
      "interface": "xyz.openbmc_project.Inventory.Decorator.Asset"
    }
  ]
  • psuDevices defines the kernel device dir for each PSU in inventory. The configuration example below indicates that powersupply0's device is located in /sys/bus/i2c/devices/3-0069.
      "psuDevices": {
    "/xyz/openbmc_project/inventory/system/chassis/motherboard/powersupply0" : "/sys/bus/i2c/devices/3-0069",
  }