[USB-Audio - VX2, playback] Playback problem

I'm plagued by a usb problem. I have an external soundcard--a Topping VX2--that connects via usb. Under Ubuntu 15.04 and 15.10, the device worked as expected. But under Ubuntu 16.04, it causes severe problems:

1. When plugged in, the device often interferes with boot. Unplug the device, and Ubuntu boots as expected.
2. If left plugged in while booting/rebooting, upon successful login, all desktop icons and other theme-based decoration is reverted to the default Ubuntu settings.
3. If plugged in after successful boot and login, the device seems to nuke Pulseaudio: it wipes out *all* devices in "Sound Settings," giving the impression that there are no sound cards in the machine. Remove the usb cord, and all is well--my devices all return.
4. During a reboot with the device plugged in, Ubuntu seems to hang and gives -110 USB errors.

* Thinking I had a defective unit, I returned this device for another one. However, the new device causes the exact same problems.

* The VX2 uses Via Technologies VT 1620A USB audio controller.

A portion from my kernel log:

[Code]
kernel: [ 318.180047] usb 3-12: new full-speed USB device number 10 using xhci_hcd
Jun 28 13:51:11 Rufus kernel: [ 318.408031] usb 3-12: New USB device found, idVendor=040d, idProduct=3400
Jun 28 13:51:11 Rufus kernel: [ 318.408036] usb 3-12: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Jun 28 13:51:11 Rufus kernel: [ 318.408039] usb 3-12: Product: VX2
Jun 28 13:51:11 Rufus kernel: [ 318.408041] usb 3-12: Manufacturer: TOPPING
Jun 28 13:51:12 Rufus kernel: [ 318.955602] input: TOPPING VX2 as /devices/pci0000:00/0000:00:14.0/usb3/3-12/3-12:1.2/0003:040D:3400.000A/input/input23
Jun 28 13:51:12 Rufus kernel: [ 319.008253] hid-generic 0003:040D:3400.000A: input,hidraw7: USB HID v1.00 Device [TOPPING VX2] on usb-0000:00:14.0-12/input2
Jun 28 13:51:12 Rufus mtp-probe: checking bus 3, device 10: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-12"
Jun 28 13:51:12 Rufus mtp-probe: bus: 3, device: 10 was not an MTP device
Jun 28 13:51:21 Rufus org.gtk.vfs.Daemon[1944]: ** (gvfsd:1995): WARNING **: dbus_mount_reply: Error from org.gtk.vfs.Mountable.mount(): Failed to retrieve share list from server: Connection timed out
Jun 28 13:51:21 Rufus org.gtk.vfs.Daemon[1944]: ** (process:2686): WARNING **: Couldn't create directory monitor on smb://x-gnome-default-workgroup/. Error: The specified location is not mounted
Jun 28 13:51:22 Rufus kernel: [ 329.060630] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:51:22 Rufus pulseaudio[2191]: [alsa-source-USB Audio] ratelimit.c: 1096 events suppressed
Jun 28 13:51:22 Rufus pulseaudio[2191]: [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally
Jun 28 13:51:27 Rufus kernel: [ 334.060518] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:51:23 Rufus pulseaudio[2191]: message repeated 10 times: [ [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally]
Jun 28 13:51:27 Rufus pulseaudio[2191]: [alsa-source-USB Audio] ratelimit.c: 114 events suppressed
Jun 28 13:51:27 Rufus pulseaudio[2191]: [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally
Jun 28 13:51:32 Rufus kernel: [ 339.060521] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:51:28 Rufus pulseaudio[2191]: message repeated 10 times: [ [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally]
Jun 28 13:51:32 Rufus pulseaudio[2191]: [alsa-source-USB Audio] ratelimit.c: 114 events suppressed
Jun 28 13:51:32 Rufus pulseaudio[2191]: [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally
Jun 28 13:51:37 Rufus kernel: [ 344.060559] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:51:33 Rufus pulseaudio[2191]: message repeated 10 times: [ [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally]
Jun 28 13:51:37 Rufus pulseaudio[2191]: [alsa-source-USB Audio] ratelimit.c: 114 events suppressed
Jun 28 13:51:37 Rufus pulseaudio[2191]: [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally
Jun 28 13:51:42 Rufus kernel: [ 349.060535] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:51:38 Rufus pulseaudio[2191]: message repeated 10 times: [ [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally]
Jun 28 13:51:42 Rufus pulseaudio[2191]: [alsa-source-USB Audio] ratelimit.c: 115 events suppressed
Jun 28 13:51:42 Rufus pulseaudio[2191]: [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally
Jun 28 13:51:47 Rufus kernel: [ 354.060528] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:51:43 Rufus pulseaudio[2191]: message repeated 10 times: [ [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally]
Jun 28 13:51:47 Rufus pulseaudio[2191]: [alsa-source-USB Audio] ratelimit.c: 115 events suppressed
Jun 28 13:51:47 Rufus pulseaudio[2191]: [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally
Jun 28 13:51:52 Rufus kernel: [ 359.060519] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:51:48 Rufus pulseaudio[2191]: message repeated 10 times: [ [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally]
Jun 28 13:51:52 Rufus pulseaudio[2191]: [alsa-source-USB Audio] ratelimit.c: 114 events suppressed
Jun 28 13:51:52 Rufus pulseaudio[2191]: [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally
Jun 28 13:51:57 Rufus kernel: [ 364.060528] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:52:02 Rufus kernel: [ 369.060563] usb 3-12: 1:1: usb_set_interface failed (-110)
Jun 28 13:52:02 Rufus kernel: [ 369.069799] usb 3-12: USB disconnect, device number 10
Jun 28 13:52:02 Rufus kernel: [ 369.070133] usb 3-12: 1:1: usb_set_interface failed (-71)
Jun 28 13:51:58 Rufus pulseaudio[2191]: message repeated 15 times: [ [alsa-source-USB Audio] asyncq.c: q overrun, queuing locally]
Jun 28 13:52:02 Rufus acpid: input device has been disconnected, fd 20
Jun 28 13:52:19 Rufus dbus[924]: [system] Activating via systemd: service name='org.bluez' unit='dbus-org.bluez.service'

[/Code]

Thank you.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.4.0-28.47-generic 4.4.13
Uname: Linux 4.4.0-28-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Jun 30 14:00:11 2016
InstallationDate: Installed on 2016-03-15 (107 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:VX2 failed
Symptom_AlsaPlaybackTestStderr: U n a b l e t o s e t h w p a r a m s f o r p l a y b a c k : I n p u t / o u t p u t e r r o r
Symptom_Card: VX2 - VX2
Symptom_Type: None of the above
Title: [USB-Audio - VX2, playback] Playback problem
UpgradeStatus: Upgraded to xenial on 2016-05-06 (55 days ago)
dmi.bios.date: 01/11/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: F20
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: X99-SLI-CF
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.asset.tag: leow6
dmi.chassis.type: 3
dmi.chassis.vendor: System76, Inc.
dmi.chassis.version: leow6
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF20:bd01/11/2016:svnSystem76,Inc.:pnLeopardWS:pvrleow6:rvnGigabyteTechnologyCo.,Ltd.:rnX99-SLI-CF:rvrx.x:cvnSystem76,Inc.:ct3:cvrleow6:
dmi.product.name: Leopard WS
dmi.product.version: leow6
dmi.sys.vendor: System76, Inc.