Deprecating health@1.0

The framework will continue to work with health@1.0 until it is fully deprecated according to the standard HAL deprecation schedule. When health@1.0 is deprecated (entry removed from framework compatibility matrix), healthd and libbatterymonitor must also be removed from system to avoid unknown behaviors for healthd. As health@1.0 is an optional HAL and all healthd dependencies to health@1.0 are guarded by NULL checks, nothing should break on deprecation.

When Android removes the legacy code path (healthd, health@1.0), Health@1.0 HAL is deprecated according to deprecation schedule. In addition, Android also removes the following:

1. healthd dependency in framework
2. healthd
3. health@1.0 HAL definition library from system
4. health@1.0 entry in framework compatibility matrix

Removing healthd

For devices launching with Android 9 and devices upgrading to Android 9 that provide the Health 2.0 HAL in the new vendor image, we recommend removing healthd from the system image to save disk space and speed boot time.

To do so:

1. Remove healthd and healthd.rc from the system image by adding the following line to the device-specific implementation in Soong:

   cc_binary {
       name: "android.hardware.health@2.0-service.device_name"
       overrides: ["healthd"],
       // ...
   }
   

   Or, if the module is in Make:

   LOCAL_MODULE_NAME := \
       android.hardware.health@2.0-service.device_name
   LOCAL_OVERRIDES_MODULES := healthd
   

   If the default implementation android.hardware.health@2.0-service is installed, implement a device-specific android.hardware.health@2.0-service.device_name instead. For more information, see Implementing Health.

2. Add the following lines to BoardConfig.mk to remove the backup instance from framework manifest. This ensures the framework manifest correctly reflects the HALs on the device and allows the relevant VTS tests to pass.

   DEVICE_FRAMEWORK_MANIFEST_FILE += \
       system/libhidl/vintfdata/manifest_healthd_exclude.xml