I’m investigating some issues when plugging in Wifi/Bluetooth dongles into a board containing the Apalis TK1 module.
First, sometimes when running a wifi scan or bluetooth scan, the entire USB stack will either freeze with no stderr output, or you will see a message like:
[ 611.491403] usb 2-3.1: USB disconnect, device number 3 [ 617.315206] tegra-xhci tegra-xhci: Timeout while waiting for configure endpoint command [ 624.110096] tegra-xhci tegra-xhci: Stopped the command ring failed, maybe the host is dead [ 624.139217] tegra-xhci tegra-xhci: Host not halted after 16000 microseconds. [ 624.146248] tegra-xhci tegra-xhci: Abort command ring failed [ 624.152176] [sched_delayed] sched: RT throttling activated [ 624.159300] tegra-xhci tegra-xhci: HC died; cleaning up [ 624.170460] usb 2-3: USB disconnect, device number 2
Using a powered hub reduces the frequency of the issue, but does not completely resolve it. When using a powered hub, though the scanning is more reliable, sometimes removing the dongle can also cause USB stack freeze (plugging and unplugging devices no longer has any stderr output, or you might see the HC died message like above).
When the USB dies like the cases above, I have to actually perform a cold boot to get USB working again. Soft reset doesn’t seem to resolve the problem.
A second issue, which is not quite as critical, when unplugging a dongle, there is always a kernel backtrace like:
Any assistance or guidance would be helpful!