Accelerometer Events on Virtual Accelerometer is not sent to Android Application

[Tarun Varma]

Team,

I have been trying to mimic an accelerometer on Ubuntu 18.04  device which does not have any sensors. I have created a virtual device for Accelerometer based on hdaps.c using uinput and ioctl. But when I pass dummy events to the device the events are not sent to the Android Application running which is listening to the events using onSensorChanged.

This is the virtual device created using uinput and ioctl.

device 7: /dev/input/event5

  name:     "ST LIS3LV02DL Accelerometer"

  events:

    REL (0002): REL_HWHEEL            REL_DIAL             

    ABS (0003): ABS_X                 : value 0, min 0, max 1024, fuzz 0, flat 0, resolution 0

                ABS_Y                 : value 0, min 0, max 1024, fuzz 0, flat 0, resolution 0

                ABS_Z                 : value 0, min 0, max 1024, fuzz 0, flat 0, resolution 0

                ABS_WHEEL             : value 0, min 0, max 64, fuzz 0, flat 0, resolution 0

  input props:

    <none>

Also I have made changes in init.sh to use 'ro.hardware.sensors' as 'hdaps'.

When the input device is sent the event using a utility , I could see those events being received by the virtual device using

#getevent -lt  /dev/input/event5

But the Android Application does not receive those events.  On checking the dumpsys generated by sensorservice I can see that the events are read by sensor service

Below is the snapshot of dumpsys

44 (ts=1578905209.329160929, wall=14:16:50.030) 1.03, 91.66, -1.42, 

45 (ts=1578905209.382981062, wall=14:16:50.097) -0.12, 45.96, -0.64, 

46 (ts=1578905209.382984877, wall=14:16:50.164) 1.04, 45.82, -0.59, 

47 (ts=1578905209.382987976, wall=14:16:50.231) 1.04, 91.66, -1.42, 

48 (ts=1578905209.387239933, wall=14:16:50.298) -0.11, 45.96, -0.64, 

49 (ts=1578905209.387243986, wall=14:16:50.364) 1.04, 45.82, -0.59, 

50 (ts=1578905209.387246132, wall=14:16:50.431) 1.04, 91.66, -1.42, 

Active sensors:

HDAPS accelerometer (handle=0x00000000, connections=2)

Socket Buffer size = 39 events

WakeLock Status: not held 

Mode : NORMAL

2 active connections

Connection Number: 0 

Operating Mode: NORMAL

com.testinput.MainActivity | WakeLockRefCount 0 | uid 10079 | cache size 0 | max cache size 0

HDAPS accelerometer 0x00000000 | status: First flush pending | pending flush events 0 

Connection Number: 1 

Operating Mode: NORMAL

com.android.server.policy.WindowOrientationListener | WakeLockRefCount 0 | uid 1000 | cache size 0 | max cache size 0

HDAPS accelerometer 0x00000000 | status: active | pending flush events 0 

Per my analysis the issue is because  "com.testinput.MainActivity" which is the test app for accelerometer the status is " First flush pending", which I presume is due to  SENSOR_TYPE_META_DATA not being sent when I send virtual accelerometer events.

I am not sure what this data is supposed to be in case of accelerometer. Can someone help me with this.

Thanks,

Tarun