USB_Issues/Intense_Latency

Hardware related problems and workarounds

USB_Issues/Intense_Latency

Postby Gamedrummer » Fri Aug 08, 2014 6:13 pm

Hello, I've been working on porting ROS onto the Parallella (viewtopic.php?f=44&t=577&p=9159&hilit=ROS#p9159). I am using a build of Linaro Raring due to all ROS Hydro ARM packages having stable support on Raring only. So far I am running into issues. And remember, all support for Raring has been pulled (or at least I can't find the repos) so a re-install of it would take a long time to get all packages in order.

To make sure the Parallella would be viable as a control system, the first test was to verify that all devices could be read during operation. Individually, yes, they can be read just fine, but once I have four different devices everything is up in the air.

Whenever I plug in the RoboteQ HDC2450, an Xbox 360 wired controller, a mouse and a keyboard the system registers '/dev/input/js0', but whenever I attempt to run the joystick_teleop node (with RoboteQ_node) on the system directly, not though SSH, the error "cannot open /dev/input/js0" appears. The only time that the node works is if it is run thorugh SSH, or the Xbox 360 controller is the ONLY device on the hub.

There is another issue relating to the RoboteQ HDC2450, I'm not sure if it is CDC_ACM, but the device only works 50% of the time, it's very strange, and same as before operates 100% of the time when run through SSH.

The most important issue of all is that there appears to be a three second delay between commands on the system itself not just SSH. For example, I will enter "vim" and it takes three seconds before the text editor appears. Or I will attempt to tab complete something and waiting three seconds for a response.

Is this an issue with the hardware itself, the kernel, or is it just the install of Linaro Raring?

More details about what exactly I am using can be answered in the ROS thread(see above). If there is not enough information in the thread I can elaborate more as needed.


--John
http://www.chicagoedt.org/
Gamedrummer
 
Posts: 25
Joined: Mon Dec 17, 2012 3:27 am
Location: Chicago, Illinois

Re: USB_Issues/Intense_Latency

Postby Gamedrummer » Wed Aug 13, 2014 6:00 pm

I just wanted to add that I tested the Parallella with only a USB hub and a keyboard and the system ran completely fine, no lag at all. I even tested the ROS nodes that were used previously when the system was having latency issues, sure enough nothing slowed the system down. Without the devices and the nodes constantly restarting to attempt to search for connection, the maximum CPU usage was 50%, and only 69MB of RAM were used. We are still looking into this I will attempt some more tests tonight and see if there may be a udev issue I'm not aware of.




--John
http://www.chicagoedt.org/
Gamedrummer
 
Posts: 25
Joined: Mon Dec 17, 2012 3:27 am
Location: Chicago, Illinois


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