I'm porting Android to a custom iMX8 board.
Part of this work is implementing libsensors for this board's hardware, particularly the accelerometer.
ST provide a sensors HAL. This HAL is producing sensors.imx8.so, when Android is built:
smarc_mx8mq:/ # ls -lA vendor/lib/hw/sensors.imx8.so
-rw-r--r-- 1 root root 122684 2021-09-06 14:50 vendor/lib/hw/sensors.imx8.so
smarc_mx8mq:/ # ls -lA vendor/lib64/hw/sensors.imx8.so
-rw-r--r-- 1 root root 144208 2021-09-06 14:50 vendor/lib64/hw/sensors.imx8.so
Android is not using this sensors HAL at all:
smarc_mx8mq:/ # lsof | grep libsensor
main 3609 root mem REG 179,5 94928 2271 /system/lib64/libsensor.so
main 3610 root mem REG 179,5 71304 1580 /system/lib/libsensor.so
audioserver 3645 audioserve mem REG 179,5 56984 2272 /system/lib64/libsensorprivacy.so
cameraserver 3655 cameraserv mem REG 179,5 40852 1581 /system/lib/libsensorprivacy.so
system_server 3890 system mem REG 179,5 56600 2274 /system/lib64/libsensorservicehidl.so
...a dozen more lines...
smarc_mx8mq:/ # lsof | grep sensors.imx8
1|smarc_mx8mq:/ #
Android is building the sensors.imx8.so, but not using it or running any part of it. (I've added lots of logging to check.)
How do I make Android use sensors.imx8.so?
Update:
I've found the following lines in adb logcat:
09-03 15:45:27.906 3413 3413 I hwservicemanager: getTransport: Cannot find entry [email protected]::ISensors/default in either framework or device manifest.
09-03 15:45:27.910 3413 3413 I hwservicemanager: getTransport: Cannot find entry [email protected]::ISensors/default in either framework or device manifest.
This makes it look as if I need to add sensors.imx8.so to a manifest, but device/embedian/imx8m/smarc_mx8mq/manifest.xml looks like:
<manifest version="1.0" type="device" target-level="4">
<hal format="hidl">
<name>android.hardware.radio</name>
<transport>hwbinder</transport>
<version>1.4</version>
<interface>
<name>IRadio</name>
<instance>slot1</instance>
</interface>
</hal>
<hal format="hidl">
<name>android.hardware.graphics.allocator</name>
<transport>hwbinder</transport>
<impl level="generic"></impl>
<version>2.0</version>
<interface>
<name>IAllocator</name>
<instance>default</instance>
</interface>
</hal>
...many more...
The stanzas do not specify library (path) names, so I do not see how adding a sensors stanza will help.
Update:
With the stanza:
<hal format="hidl">
<name>android.hardware.sensors</name>
<transport>hwbinder</transport>
<version>1.0</version>
<interface>
<name>ISensors</name>
<instance>default</instance>
</interface>
</hal>
The errors are now:
09-03 15:52:50.873 3890 3987 I ServiceManagement: getService: Trying again for [email protected]::ISensors/default...
09-03 15:52:51.873 3890 3987 W ServiceManagement: Waited one second for [email protected]::ISensors/default
09-03 15:52:51.874 3890 3987 I ServiceManagement: getService: Trying again for [email protected]::ISensors/default...
09-03 15:52:52.874 3890 3987 W ServiceManagement: Waited one second for [email protected]::ISensors/default
09-03 15:52:52.876 3890 3987 I ServiceManagement: getService: Trying again for [email protected]::ISensors/default...
09-03 15:52:53.876 3890 3987 W ServiceManagement: Waited one second for [email protected]::ISensors/default
I chose version 1.0, after reading https://source.android.com/devices/sensors/hal-interface and https://source.android.com/devices/sensors/sensors-hal2
(The ST Sensors HAL has get_sensors_list() from 1.0 but not getSensorsList() from 2.0.)
The solution was to add:
PRODUCT_PACKAGES += [email protected]
PRODUCT_PACKAGES += [email protected]
to smarc_mx8mq.mk and correct the stanza to:
<hal format="hidl">
<name>android.hardware.sensors</name>
<transport>hwbinder</transport>
<version>1.0</version>
<interface>
<name>ISensors</name>
<instance>default</instance>
</interface>
<fqname>@1.0::ISensors/default</fqname>
</hal>