This email is to ask/discuss if there is a stable path/name (or whatever) for hwmon devices in the different versions of kernels. In OpenBMC, the service phosphor-hwmon reads the sensors' value and expose to DBus, depending on a configure file that matches the device tree path. The service is started by udev rule, called with the DEVPATH and OF_FULLNAME, so it knows where to find the configure file depending on DEVPATH or OF_FULLNAME. E.g. on Romulus BMC, the w83773 sensor has OF_FULLNAME at /ahb/apb/i2c@1e78a000/i2c-bus@440/w83773g@4c, and the service knows the config is matched from path /etc/default/obmc/hwmon/ahb/apb/i2c@1e78a000/i2c-bus@440/w83773g@xxxxxxx However, the DEVPATH or OF_FULLNAME is not stable in different kernels: * In 4.1x kernel, the path is as above. * In 5.0 kernel, "i2c@1e78a000" is changed to "bus@1e78a000" in the path. This breaks the userspace's phosphor-hwmon. If we fix the issue by updating the configure files' path in userspace, it means the userspace only with the new 5.x kernel. So the question here is, it there a stable way for userspace to match a hwmon device? Thanks! -- BRs, Lei YU
