USB ExpressCard makes kworker process utilise 72% CPU infinitely

[Christoph Anton Mitterer]

Hey.

I bough a USB3.0 ExpressCard from StarTech[0] which is apparently[1]
based on theÂNEC uPD720200.

Using a kernelÂ4.2.6 on amd64, the System is Debian sid, the following
happens when I plug the card:

kernel logs show:
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.387452] pci 0000:01:00.0: [1033:0194] type 00 class 0x0c0330
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.387545] pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x00001fff 64bit]
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.387723] pci 0000:01:00.0: PME# supported from D0 D3hot
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.394689] pci 0000:01:00.0: BAR 0: assigned [mem 0xf0d00000-0xf0d01fff 64bit]
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.394750] pci 0000:01:00.0: enabling device (0000 -> 0002)
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395178] xhci_hcd 0000:01:00.0: xHCI Host Controller
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395192] xhci_hcd 0000:01:00.0: new USB bus registered, assigned bus number 5
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395418] xhci_hcd 0000:01:00.0: hcc params 0x014042cb hci version 0x96 quirks 0x00000004
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395892] usb usb5: New USB device found, idVendor=1d6b, idProduct=0002
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395896] usb usb5: New USB device strings: Mfr=3, Product=2, SerialNumber=1
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395899] usb usb5: Product: xHCI Host Controller
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395902] usb usb5: Manufacturer: Linux 4.2.0-1-amd64 xhci-hcd
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.395905] usb usb5: SerialNumber: 0000:01:00.0
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.396308] hub 5-0:1.0: USB hub found
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.396331] hub 5-0:1.0: 2 ports detected
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.396591] xhci_hcd 0000:01:00.0: xHCI Host Controller
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.396599] xhci_hcd 0000:01:00.0: new USB bus registered, assigned bus number 6
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.398835] usb usb6: We don't know the algorithms for LPM for this host, disabling LPM.
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.398883] usb usb6: New USB device found, idVendor=1d6b, idProduct=0003
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.398887] usb usb6: New USB device strings: Mfr=3, Product=2, SerialNumber=1
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.398890] usb usb6: Product: xHCI Host Controller
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.398892] usb usb6: Manufacturer: Linux 4.2.0-1-amd64 xhci-hcd
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.398895] usb usb6: SerialNumber: 0000:01:00.0
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.399272] hub 6-0:1.0: USB hub found
Nov 21 17:15:22 heisenberg kernel: [ÂÂ102.399294] hub 6-0:1.0: 2 ports detected

and when removing:
Nov 21 17:15:40 heisenberg kernel: [ÂÂ120.541515] xhci_hcd 0000:01:00.0: remove, state 4
Nov 21 17:15:40 heisenberg kernel: [ÂÂ120.544671] usb usb6: USB disconnect, device number 1
Nov 21 17:15:40 heisenberg kernel: [ÂÂ120.546683] xhci_hcd 0000:01:00.0: Host not halted after 16000 microseconds.
Nov 21 17:15:40 heisenberg kernel: [ÂÂ120.547611] xhci_hcd 0000:01:00.0: USB bus 6 deregistered
Nov 21 17:15:40 heisenberg kernel: [ÂÂ120.547618] xhci_hcd 0000:01:00.0: remove, state 4
Nov 21 17:15:40 heisenberg kernel: [ÂÂ120.547622] usb usb5: USB disconnect, device number 1
Nov 21 17:15:40 heisenberg kernel: [ÂÂ120.547735] xhci_hcd 0000:01:00.0: USB bus 5 deregistered


Now the problem is that immediately when I attach the card, a kworker
process starts to utilise the CPU to always around 72%.
And it never stops again until I shutdown; removing the card doesn't
help.


Any ideas?

Thanks,
Chris.


[0]Âhttp://www.startech.com/Cards-Adapters/USB-3.0/Cards/2-Port-Flush-Mount-USB-3-ExpressCard-Adapter~ECUSB3S254F
[1] http://sgcdn.startech.com/005329/media/sets/ECUSB3S254F_Manual/ECUSB3S254F.pdf

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