T265 connection/recognition issues

[eospi]

---

Required Info
Camera Model	{ D435 and T265 }
Firmware Version	05.11.01.100/0.0.18.5448
Operating System & Version	Ubuntu 18.04
Kernel Version (Linux Only)	(e.g. 4.14.13)
Platform	PC/Raspberry Pi/ NVIDIA Jetson / etc..
SDK Version	2.20
Language	Python and C++
Segment	{Robot/Smartphone/VR/AR/others }

Issue Description

I'm trying to use the D435 and T265 together. In Python, pyrealsense can detect and use the D435 but not the T265. For example, when I run the following code, only the D435 is recognized.

context = rs.context()
for device in context.query_devices():
    print(device)

I get this error:
Device-4D00: Error: Failed to claim USB interface. LIBUSB_ERROR_CODE: 0xFFFFFFFA (LIBUSB_ERROR_BUSY)

This issue has rotated through Python, C++, and the RealSense Viewer with the same error, and it can work in one environment but not the others. How can I fix this? Thanks!

[ev-mp]

@eospi , I could reproduce this error on a PC that has no proper Librealsense udev-rules installed.
Please verify udev-rules are installed with:

1. the installation script when building from source code:

./scripts/setup_udev_rules.sh

2. Via debian distribution for Ubuntu LTS:

sudo apt install librealsense2-udev-rules

Then reconnect T265 and retry.

[eospi]

Thanks for the response! I installed udev-rules, and it worked the first time I tried it. However, it has reverted to the previous issue, and the T265 is still not detected in Python and briefly in the RealSense Viewer.

[eospi]

The T265 seems to be connecting most of the time, but sometimes it won't be recognized with the same libusb error. When recognized, running t265_example.py works as expected, but when I use both the T265 and D435 together, the pose data from the T265 is empty. Trying to access data.translation causes an Attribute Error:
'pyrealsense2.pyrealsense2.BufData' object has no attribute 'translation'

[ev-mp]

@eospi ,
I'd suggest to run rs-multicam example to see whether the D435/T265 tandem works properly.
then you can may post the python code segment for review.
Note that currently there are limitations imposed on how T265 shall be activated in multi-cam scenario. (#3734).

[eospi]

rs-multicam works well. I am using the first pipeline created for the T265. Here is my code:

import pyrealsense2 as rs
import numpy as np

context = rs.context()
pipelines = []

for device in context.query_devices():
    pipe = rs.pipeline(context)
    config = rs.config()
    config.enable_device(device.get_info(rs.camera_info.serial_number))
    pipe.start(config)
    pipelines.append(pipe)
    print(device)

def grab_colour_frame():
    frames = pipelines[0].wait_for_frames()
    colour = np.asanyarray(frames.get_color_frame().get_data())
    return colour

def grab_pose_frame():
    frames = pipelines[1].wait_for_frames()
    pose = frames.get_pose_frame()
    return pose

while True:
    colour = grab_colour_frame()
    pose = grab_pose_frame()
   
    if pose:
        data = pose.get_data()
        print(data.translation)

[ev-mp]

Small fix will make the code run properly:

if pose:
data = pose.get_dataget_pose_data()
print(data.translation)

See reference example

[eospi]

Thanks so much! It's working now.

[dhirajpatnaik16297]

Hey,
I am getting the following error while i am connecting both d435 and t265 to jetson xavier
frames = pipelines[0].wait_for_frames()
IndexError: list index out of range

but, individually they are working and in realsense-viewer both are detected and working fine.
Same problem occurs when running in raspberry pi 4 b which has 2 3.0 ports.
Only in the python code, i am not able to make it work.
Please help me out.