librealsense: Android, D415, rs2:backend_error, Permission Denied

Required Info
Camera Model	D415
Firmware Version	05.08.15.00
Operating System & Version	MacOS 10.14.1 / Android 7.1.1
Platform	PC/Android
SDK Version	2
Language	Java/C
Segment	Tablet?

Issue Description

I have a rooted Lenovo Tab 4 8" running Android 7.1.1

I have successfully compiled the Android version of the project.

I have connected the camera to my tablet using two cables:

• USB mini A to USB A (UGREEN Micro USB to USB, Micro USB 2.0 OTG Cable 2 Pack On The Go Adapter Micro USB Male to USB Female)
• USB A to USB C (supplied with D415)

When I launch “realsense_app”, it correctly detects the presence of the camera (ie. error if usb is not connected.) However, quickly after that, the application crashes:

 signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------
2018-12-13 13:26:11.563 12956-12956/? A/DEBUG: Abort message: '/Volumes/Android/buildbot/src/android/ndk-release-r18/external/libcxx/../../external/libcxxabi/src/abort_message.cpp:73: abort_message: assertion "terminating with uncaught exception of type rs2::backend_error: Could not open device. Last Error: Permission denied" failed'
2018-12-13 13:26:11.563 12956-12956/? A/DEBUG:     r0 00000000  r1 00003261  r2 00000006  r3 00000008
2018-12-13 13:26:11.563 12956-12956/? A/DEBUG:     r4 d8460978  r5 00000006  r6 d8460920  r7 0000010c
2018-12-13 13:26:11.563 12956-12956/? A/DEBUG:     r8 ffc3769c  r9 f03db180  sl e9b06929  fp 0000000b
2018-12-13 13:26:11.563 12956-12956/? A/DEBUG:     ip 0000000d  sp d8460220  lr f25d6467  pc f25d8ce8  cpsr 200e0010
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG: backtrace:
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #00 pc 00049ce8  /system/lib/libc.so (tgkill+12)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #01 pc 00047463  /system/lib/libc.so (pthread_kill+34)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #02 pc 0001d745  /system/lib/libc.so (raise+10)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #03 pc 00019281  /system/lib/libc.so (__libc_android_abort+34)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #04 pc 000172e8  /system/lib/libc.so (abort+4)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #05 pc 0001b73f  /system/lib/libc.so (__libc_fatal+22)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #06 pc 0001947b  /system/lib/libc.so (__assert2+18)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #07 pc 0082e6e9  /data/app/com.example.realsense_app-1/lib/arm/librealsense2.so
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #08 pc 0082e7f5  /data/app/com.example.realsense_app-1/lib/arm/librealsense2.so
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #09 pc 0082cb95  /data/app/com.example.realsense_app-1/lib/arm/librealsense2.so
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #10 pc 0082c7a7  /data/app/com.example.realsense_app-1/lib/arm/librealsense2.so (__cxa_rethrow+78)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #11 pc 0000adaf  /data/app/com.example.realsense_app-1/lib/arm/libnative-lib.so
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #12 pc 0000a9e3  /data/app/com.example.realsense_app-1/lib/arm/libnative-lib.so
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #13 pc 00046f33  /system/lib/libc.so (_ZL15__pthread_startPv+22)
2018-12-13 13:26:11.573 12956-12956/? A/DEBUG:     #14 pc 00019ccd  /system/lib/libc.so (__start_thread+6)

With the primary error being the following exception:

rs2::backend_error: Could not open device. Last Error: Permission denied" failed'

I traced this error to the function power_D0() inside of libuvc/libuvc.cpp. It looks like uvc_find_device() returns 0, so then it calls uvc_open2 with interface=0 and returns res=-3 causing the following exception to be thrown. Error -3 appears to be LIBUSB_ERROR_ACCESS from libusb_openwhich corresponds to “Access denied (insufficient permissions)”.

I’ve checked that the USB device permissions are okay: when my camera is connected, I see 2 USB devices, 001/001 and 001/002, and I’ve chmod -R 0777 the appropriate files.

Any ideas?