Hello,

since 3.12 dmesg (and logfiles) are filled up with:

  xhci_hcd 0000:00:14.0: ep 0x81 - asked for 96 bytes, 78 bytes untransferred
  xhci_hcd 0000:00:14.0: Giveback URB ffff8807f82ec240, len = 18, expected = 96, status = -121
  xhci_hcd 0000:00:14.0: Stalled endpoint
  xhci_hcd 0000:00:14.0: Giveback URB ffff8808181e0240, len = 0, expected = 13, status = -32
  xhci_hcd 0000:00:14.0: Queueing reset endpoint command
  xhci_hcd 0000:00:14.0: Cleaning up stalled endpoint ring
  xhci_hcd 0000:00:14.0: Finding segment containing stopped TRB.
  xhci_hcd 0000:00:14.0: Finding endpoint context
  xhci_hcd 0000:00:14.0: Finding segment containing last TRB in TD.
  xhci_hcd 0000:00:14.0: Cycle state = 0x0
  xhci_hcd 0000:00:14.0: New dequeue segment = ffff8808195b4280 (virtual)
  xhci_hcd 0000:00:14.0: New dequeue pointer = 0xfffb2140 (DMA)
  xhci_hcd 0000:00:14.0: Queueing new dequeue state
  xhci_hcd 0000:00:14.0: Set TR Deq Ptr cmd, new deq seg = ffff8808195b4280 (0xfffb2000 dma), new deq ptr = ffff880816832140 (0xfffb2140 dma), new cycle = 0
  xhci_hcd 0000:00:14.0: // Ding dong!
  xhci_hcd 0000:00:14.0: WARN halted endpoint, queueing URB anyway.
  xhci_hcd 0000:00:14.0: Ignoring reset ep completion code of 1
  xhci_hcd 0000:00:14.0: Successful Set TR Deq Ptr cmd, deq = @fffb2140

blocks, about 25 at a time, every 2 seconds.
As far as I can tell, this is new with 3.12 (stock) kernel.

System is a i7 4770 on Gigabyte H87-HD3 motherboard, with a IcyBox
IB-867-B, lshw-output attached.

/proc/version:
  Linux version 3.12.0 (berberic@hermione) (gcc version 4.8.2 (Debian
  4.8.2-1) ) #1 SMP PREEMPT Mon Nov 4 21:20:24 CET 2013

scripts/ver_linux:
  Linux hermione 3.12.0 #1 SMP PREEMPT Mon Nov 4 21:20:24 CET 2013 x86_64 GNU/Linux

  Gnu C                  4.8
  Gnu make               3.81
  binutils               2.23.90.20131017
  util-linux             scripts/ver_linux: 23: scripts/ver_linux: fdformat: not found
  mount                  support
  module-init-tools      found
  Linux C Library        2.17
  Dynamic linker (ldd)   2.17
  Procps                 3.3.4
  Kbd                    1.15.5
  Sh-utils               8.21
  Modules Loaded ppdev lp bnep rfcomm bluetooth vboxpci vboxnetadp
                 vboxnetflt vboxdrv kvm_intel kvm cpufreq_powersave
		 it87 hwmon_vid coretemp firewire_sbp2 firewire_core
		 fuse snd_usb_audio snd_usbmidi_lib snd_seq_midi
                 snd_rawmidi pcspkr parport_pc parport

lsusb:
  Bus 002 Device 002: ID 8087:8000 Intel Corp. 
  Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  Bus 001 Device 002: ID 8087:8008 Intel Corp. 
  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  Bus 004 Device 002: ID 05e3:0732 Genesys Logic, Inc. 
  Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
  Bus 003 Device 005: ID 08bb:2902 Texas Instruments PCM2902 Audio Codec
  Bus 003 Device 004: ID 0409:005a NEC Corp. HighSpeed Hub
  Bus 003 Device 003: ID 046d:c05a Logitech, Inc. M90/M100 Optical Mouse
  Bus 003 Device 002: ID 03f0:6204 Hewlett-Packard DeskJet 5150c
  Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub


	MfG
	bmg

-- 
„Des is völlig wurscht, was heut beschlos- | M G Berberich
 sen wird: I bin sowieso dagegn!“          | berberic@fmi.uni-passau.de
(SPD-Stadtrat Kurt Schindler; Regensburg)  | www.fmi.uni-passau.de/~berberic