When booting a device using an Intel E3845 cpu, we see the following usb errors in the dmesg:
 usbus1: port reset timeout
 uhub_reattach_port: port 1 reset failed, error=USB_ERR_TIMEOUT
 uhub_reattach_port: device problem (USB_ERR_TIMEOUT), disabling port 1
Although we receive those errors, usb ports are working as expexted.
In fact those errors comes from the EHCI driver, but the ports seems to be using the XHCI one.
My guess is that the system try to attach both driver to the same device, since the cpu does expose both interfaces (XHCI should be preferred, EHCI is exposed mainly for compatibility reasons)
In order to check that I tried to force the XHCI mode in the BIOS, and this made those errors disappears (the problem here being that we can't access the BIOS from our customers), which seems to confirm my supposition.
How do you think we could address the problem?