build, docs: Support GCC 15 / C++23 and fix libnvme and markdownlint The unit test Docker image was recently upgraded from Ubuntu with GCC 14.3.0 and Meson 1.7.0 to Ubuntu 26.04 with GCC 15.2.0 and Meson 1.11.2. This toolchain upgrade introduced several issues: 1. Modern sdbusplus requires C++23 under GCC 15. Update meson.build default cpp_std to c++23 and meson_version to >=1.1.1. 2. GCC 15 enforces stricter -Wformat for non-void pointers passed to %p, causing a build failure in libnvme/ccan. Add a patch to cast pointers to const void*. 3. Top-level warning_level=3 and -Wpedantic propagated to the libnvme subproject. Isolate libnvme with warning_level=1 and werror=false. 4. Meson runs tests from subprojects by default. Under GCC 15 UBSan (halt_on_error=1), libnvme's internal tests fail with unaligned memory access and null pointer in memset. Add a patch to libnvme meson.build to skip building internal tests and examples when libnvme is built as a subproject. 5. Fix markdownlint issues across documentation. Tested: Verified clean compilation and test execution in Docker container with GCC 15 and address,undefined sanitizer. Google-Bug-Id: 560184526 Change-Id: Ib476238d65c50a15bddad8e24b5e8462c924800c Signed-off-by: Guangzong Chen <guangzong@google.com> TAG=agy CONV=6866aaa8-fc79-4b5d-bbc3-928fa7aa65f3
dbus-sensors is a collection of sensor applications that provide the xyz.openbmc_project.Sensor collection of interfaces. They read sensor values from hwmon, d-bus, or direct driver access to provide readings. Some advance non-sensor features such as fan presence, pwm control, and automatic cpu detection (x86) are also supported.
runtime re-configurable from d-bus (entity-manager or the like)
isolated: each sensor type is isolated into its own daemon, so a bug in one sensor is unlikely to affect another, and single sensor modifications are possible
async single-threaded: uses sdbusplus/asio bindings
multiple data inputs: hwmon, d-bus, direct driver access
A typical dbus-sensors object support the following dbus interfaces:
Path /xyz/openbmc_project/sensors/<type>/<sensor_name> Interfaces xyz.openbmc_project.Sensor.Value xyz.openbmc_project.Sensor.Threshold.Critical xyz.openbmc_project.Sensor.Threshold.Warning xyz.openbmc_project.State.Decorator.Availability xyz.openbmc_project.State.Decorator.OperationalStatus xyz.openbmc_project.Association.Definitions
Sensor interfaces collection are described in Sensor interfaces.
Consumer examples of these interfaces are Redfish, Phosphor-Pid-Control, IPMI SDR.
dbus-sensor daemons are reactors that dynamically create and update sensors configuration when system configuration gets updated.
Using asio timers and async calls, dbus-sensor daemons read sensor values and check thresholds periodically. PropertiesChanged signals will be broadcasted for other services to consume when value or threshold status change. OperationStatus is set to false if the sensor is determined to be faulty.
A simple sensor example can be found in the my_first_sensors example.
Sensor devices are described using Exposes records in configuration file. Name and Type fields are required. Different sensor types have different fields. Refer to entity manager schema for complete list.