Why does my webcam or USB headset not work when connected to a PCoIP Zero Client at the same time?

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August 3, 2018

Last modified: 09/03/2023, 6:08 pm

Knowledge Base Article Troubleshooting Peripheral Devices Zero Clients

Problem

Your webcam and USB headset are connected to the PCoIP Zero Client at the same time and only one of the two works.

When only one of the two devices is connected, it works as anticipated.
In the example below, the Logitech USB Headset (901) is the device identified which is not working. It also identifies the reason it is not working, in this case it is due to having no bandwidth available (No BW avail for Dev=0x901 Interface=0x1)
LVL:3 RC:   0             MGMT_USB_AUDIO :Default audio output device: Logitech USB Headset (0901)
LVL:3 RC:   0             USB :Not doing select interface for device 0x901 if 1 alt 0 - already selected
LVL:2 RC:   0             USB :No-bw for Dev=0x901 EPaddr=0x1 Intv=1 MPS=192(0xc0) ab=46 bc=192
LVL:1 RC:-500           USB :Select interface failed - No BW avail for Dev=0x901 Interface=0x1
LVL:1 RC:-500           MGMT_USB_AUDIO :mgmt_usb_audio_util_streaming_sampling_set: audio_streaming_sampling_set failed - status:
LVL:1 RC:-500          MGMT_USB_AUDIO :Failed to configure audio device id: 0x901, vid: 0x46d, pid: 0xa0c

 

Cause

This issue is not specific to webcams and USB headsets, but can occur when all of the attached USB devices use the same USB controller. In this case, the USB devices where connected to the OHCI controller. Under this condition there was not enough bandwidth available on that controller and failure of the headset occurred.

Zero Clients force all webcams to use the OHCI controller but do not force any other USB device to any specific controller. Webcam's, being isochronous devices use the majority of the bandwidth (BW), and in this case there was not much bandwidth left on the OHCI BW pipe for the headset to function properly.

 

Resolution

If issue occurs, you need to ensure that the other attached USB devices are using the EHCI controller (other than webcam if there is a webcam attached).
For the devices that by default use an OHCI controller, (like the majority of USB headsets) connect them to an internal1 or external USB 2.0 hub.

1 Some zero client OEM's have added internal EHCI hubs to their brand of zero client. Contact your OEM for further details regarding your particular brand of zero client or see How to identify which USB port on my PCoIP zero client is behind an integrated/internal USB hub?