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Watch out for USB controller speed limit!

Posted: Thu Oct 29, 2015 8:10 pm
by Spikee
I was having a bunch of problems with my liteplacer.
After I changed my upcam to the Logitech C270 the control of the liteplacer became really laggy, sometimes it would just stop in the middle what it was doing or crash often.

The problem?
It seems that all the usb (2.0 and 3.0) lines go trough 1 or two controllers. The USB 3.0 Lines did not work so everything was on the 2.0 lines.
The logitech webcam only showed the 1024x xxx settings , now on my laptop it shows the full 3MP.

Looks like there occured some kind of packet overflow causing it to drop USB packets.

Which interrupted commands going to the TinyG etc...

Mind you this is a 8 core AMD , SSD machine so their is enough power. The weak link seems to be the USB controller.

Now on my laptop it works fine. But I might get a USB3.0 hub so I can also hook my headphones to it.


I think others will have simular hardware problems. Especially on old machines.

Re: Watch out for USB controller speed limit!

Posted: Thu Oct 29, 2015 8:58 pm
by Spikee
Found new USB 3.0 files. Works without problems now.

Re: Watch out for USB controller speed limit!

Posted: Thu Oct 29, 2015 10:18 pm
by mrandt
Spikee wrote:Found new USB 3.0 files. Works without problems now.
So it was a driver issue?

Re: Watch out for USB controller speed limit!

Posted: Thu Oct 29, 2015 10:29 pm
by Spikee
It was USB controller speed limit on USB 2 /1 controller.

I found new driver for my USB 3.0 ports (other controller) and now the issues are gone.

Re: Watch out for USB controller speed limit!

Posted: Wed Nov 25, 2015 1:52 pm
by WayOutWest
Spikee wrote:It was USB controller speed limit on USB 2 /1 controller.

I found new driver for my USB 3.0 ports (other controller) and now the issues are gone.
I've had the same experience. Even if all of your cameras are USB 2.0, using a USB 3.0 hub to connect them will help.

Most OSes (even Linux) don't know how to use more than a fairly small percentage of the USB bandwidth for isochronous transfers.