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 USB 3 XHCI limited to 32 USB devices 
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Joined: Sat Feb 29, 2020 8:21 pm
Posts: 3
Post USB 3 XHCI limited to 32 USB devices
Hi,

I need to connect lots of USB devices to fitlet2. With EHCI (USB 2.0) USB controllers, I was able to connect more than 90 devices but with XHCI only 32 devices are allowed.

Does the fitlet2 have an EHCI controller? Is there an option in the BIOS to switch to USB 2.0 in order to be able to connect more devices?

Thanks


Sun Mar 01, 2020 9:10 am
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Joined: Mon Dec 25, 2017 4:21 pm
Posts: 416
Post Re: USB 3 XHCI limited to 32 USB devices
Please provide some examples of devices that you were not allowed?
What's the behavior of a device that doesn't work ?
Please provide machine's S/N and P/N as printed on the white sticker located at the bottom cover.


Sun Mar 01, 2020 9:39 am
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Joined: Sat Feb 29, 2020 8:21 pm
Posts: 3
Post Re: USB 3 XHCI limited to 32 USB devices
Once I connect too much devices, the kernel outputs this message:

Code:
[  272.343677] xhci_hcd 0000:00:15.0: Error while assigning device slot ID                                                                                                 [  272.343699] xhci_hcd 0000:00:15.0: Max number of devices this xHCI host supports is 32.                                                                                 
[  272.343710] usb 1-3-port7: couldn't allocate usb_device                                                   


I connected some USB hubs and barcode scanners (Opticon OPN-2001).

If I try to list all the USB controllers:
Code:
$ lspci -nn |grep -i usb
00:15.0 USB controller [0c03]: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series USB xHCI [8086:5aa8] (rev 0b)


The serial number of the fitlet2 is S/N: 1200116-11817.


Sun Mar 01, 2020 10:15 am
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Joined: Mon Dec 25, 2017 4:21 pm
Posts: 416
Post Re: USB 3 XHCI limited to 32 USB devices
Our R&D replied that there isn't EHCI controller on the fitlet2, only XHCI that appears to be the bottle neck according to logs provided here on this thread.


Tue Mar 10, 2020 1:54 pm
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