Presuming the system info you need is in the automatically generated collection from ubuntu-bug. Ubuntu 14.10, fully updated. Kernel 3.16.0-31-generic.
The problem described also exists in earlier kernels although I cannot say when it first appeared.
I have a HooToo HT-UH005 4-Port USB 3.0 hub (VIA VL812-B2 chipset) . I'm using it with a HP Pavilion 17-e049wm laptop. This computer has two USB 3.0 ports.
When the computer is quiescent the CPU consumed is normally 0% to 1%. That's the same whether there are USB 2.0 or 3.0 devices plugged into its onboard USB 3.0 ports, or not.
As soon as I plug the HT-UH005 hub into one of those USB 3.0 ports, a system process khubd appears and it takes about 7% of CPU. Also, several "kworker" and "ksoftirqd" threads appear which between them consume another 18% of CPU, for a total of 25% CPU load. That's just because the HT-UH005 was plugged in. No peripherals attached to the HT-UH005.
Stranger still, when I unplug the HT-UH005 the khubd, kworker, and ksoftirqd threads *continue* to consume 25% CPU. That's with the HT-UH005 disconnected after it was previously connected. This goes on indefinitely. The only way I can get things back to normal is to reboot or to manually stop and restart (unbind and then bind) the xhci_hcd driver that's servicing the internal hub that runs the computer's two USB 3.0 ports.
The listing from dmesg shows no apparent problems when the HT-UH005 is connected or disconnected. Listing from lsusb shows the HT-UH005 successfully connected to a port on the internal USB 3.0 hub using driver xhci_hcd.
This could be caused by some sort of incompatibility between the AMD internal hub and the VIA external hub. But, that the condition persists after the HT- UH005 is disconnected suggests it is almost surely a linux driver problem.
ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: linux-image-3.16.0-31-generic 3.16.0-31.41
ProcVersionSignature: Ubuntu 3.16.0-31.41-generic 3.16.7-ckt5
Uname: Linux 3.16.0-31-generic x86_64
NonfreeKernelModules: wl fglrx
ApportVersion: 2.14.7-0ubuntu8.2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: warren 5539 F.... pulseaudio
/dev/snd/controlC0: warren 5539 F.... pulseaudio
CurrentDesktop: Unity
Date: Wed Feb 25 22:12:53 2015
HibernationDevice: RESUME=UUID=d6ce9a82-d272-4efa-bfe4-e13c883b2418
InstallationDate: Installed on 2012-05-23 (1008 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MachineType: Hewlett-Packard HP Pavilion 17 Notebook PC
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-31-generic root=UUID=515bfe03-1a57-4762-9cc1-6896e081c4c5 ro quiet splash rootfstype=ext4 vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-3.16.0-31-generic N/A
linux-backports-modules-3.16.0-31-generic N/A
linux-firmware 1.138.1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/04/2013
dmi.bios.vendor: Insyde
dmi.bios.version: F.31
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 1984
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 01.13
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnInsyde:bvrF.31:bd12/04/2013:svnHewlett-Packard:pnHPPavilion17NotebookPC:pvr0880100003305B10000620100:rvnHewlett-Packard:rn1984:rvr01.13:cvnHewlett-Packard:ct10:cvrChassisVersion:
dmi.product.name: HP Pavilion 17 Notebook PC
dmi.product.version: 0880100003305B10000620100
dmi.sys.vendor: Hewlett-Packard
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