Detection issues with T265

[orshefi]

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Required Info
Camera Model	T265 & D415
Firmware Version	0.0.18.5129
Operating System & Version	Linux Ubuntu 16
Kernel Version (Linux Only)	4.18.0-16-generic
Platform	PC
SDK Version	2.19.1 (apt-get)
Language	C++
Segment	Drone

Issue Description

We have tried to work with the t265 camera and encountered some issues:

• Realsense viewer can't open T265 and D415/D435 together (when both connected D415/D435 is only visable)

• rs-enumerate-devices cant enumorate t265 device, with other Realsense cameras it works fine

• ctx.query_devices() cannot find t265, with D415/D435 it works fine

[dorodnic]

We are working on a solution.
For now, something like:

ctx.query_devices();
sleep(1000);
ctx.query_devices();

Should work

[orshefi]

What about 'what(): No device connected' error? when trying to initialize the camera using serial number.

Can't initialize t265 camera using serial number approach

[macmason]

I believe this is the same issue as #3434, and (at least for me) #3515 doesn't fix it.

[RealSenseCustomerSupport]

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We've just released the latest version of librealsense version 2.19.2, please give this new version a try.

[macmason]

Will do. How long until the .deb packages land?

[jamalaberque]

With #3515, rs-enumerate-devices only work the second time with a T265 (but it works). The first time, it will fail to detect it. (Ubuntu 18.04)
ctx.query_devices never work, including with a sleep between two calls.

[RealSenseCustomerSupport]

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@jamalaberque - I've tested with the latest SDK version 2.20.0 using the rs-enumerate-devices and able to see the T265 on the first time run. I had a D435 also connected to the system upon running the sample.