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Can't get beyond 1.2MSPS without dropouts.

Posted: Sun Nov 22, 2020 6:48 pm
by iawpAb2kneuf
Intel NUC7i3 running Debian 10 with v3 dongle cannot push rtl_test beyond 1.2MSPS without dropouts. It is plugged into a USB 3.0 port. I can use the same port to drive an FL2K up to about 140MSPS.

I tried updating Debian and installing the latest BIOS update and no improvement. When I push it to 1.7MSPS or higher the "lost at least xxxx bytes" errors stream in rapidly.

USB controller is:
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)

Any ideas? Compatability issue with 3.0? Debian driver bug? Firmware bug? Power issue?

Re: Can't get beyond 1.2MSPS without dropouts.

Posted: Thu Nov 26, 2020 2:12 am
by iawpAb2kneuf
I sort-of figured it out.

A workaround for this is to have a keyboard or mouse plugged into the USB. For unknown reasons the USB performance degrades with no keyboard or mouse present.

This happens on the NUC7i3DNB.
This does not happen on the NUC7i3BNB.

They use different BIOSes. It looks like to get Intel to look into it, someone has to prove it on a Windows install- which I don't have: ... 780#M78493