Sound card on arm devices

I am trying to connect PC to remote amplifier using router (TPlink4300) with virtualhere and USB sound cards. And no success. I've got 2 different audio cards, very popular, but both with CM chips. Here is the statement:
-router running OpenWRT AA version with Gargoyle,
-both audio cards checked under OpenWRT (Gargoyle internet radio plugin playing smoothly)
-virtulahere server on router visible from PC (vhusbdmipssf), transfer to/from USB drive connected to router 4-5MB/s (with virtualhere)
-usb audio connected to router visible on virtualhere client, drivers on Win8.1 installed
-no sound in both directions
-when virtaulhere server installed on PC with ubuntu (vhusbdi386) the configuration works as expected
-when virrtualhere server instaled on NAS with arm inside (vhusbdarmel) the effect is the same as with router -no sound (usb disks, scanner work properly)
Any hints? Reading the forum I have the impression that sound cards should work with Windows.....


I think the tplink4300 which uses a MIPS 560Mhz and the arm chips are not powerful enough for your sound card or their kernels are too old. Sound cards use isochronous transfers, and a surprising number of kernels are buggy with this transfer method. However the pi now works well with isochronous transfers and so does intel x86 amd64 kernels. I think this is what is causing the problem. I test sound cards with my logitech lapdesk playing kalima.mp3 in windows with a virtualhere server running on a pi 3.18 kernel and and also an arm processor running at least kernel 3.2 (qnap)

Also, attitude adjustment is a few years old, you should try with barrier breaker if its not too much trouble..

thanks for quick response. I don't think that arm itself is a bottleneck, audio stream is almost nothing comparing to the network traffic. When playing mp3/320k internet radio on router it is only a few percent of CPU time. So, it is rather buggy kernel. Unfortunately, currently there is no stable Gargoyle based on OpenWRT BB. I have to wait :-)
Another strange sighting.... I installed vhusbdarmel on Pogoplug4 device with archlinux and very new kernel 4.0.4-1. The architecture is Marvell Kirkwood. Server works properly with disks and pendrives. Audio cards are also presented to the client. But, when used by client (doesn't matter if Win or Linux), the power supply for usb is switched off, and the audio card dissapears. From this point only Pogoplug reboot makes usb back alive.
BTW, I checked the kernel on the NAS. It is AltF on DNS323, kernel 3.10.32 (quite old as well).


In reply to by jacgl


When the power supply switches off it usually means that the usb device is trying to obtain more power than the host can provide. For example under the raspberry pi original version, if you run a webcam it will pull more than 100ma from the port and reset the board. You would need a powered hub inbetween.

When you use a usb device, what occurs is the usb device is set to a certain configuration which requires a certain amount of power. The usb host controller either supplies the power or rejects the request. If it doesnt reject the request and actually there is not enough power it will reboot the cpu as this is built-in to most cpus to protect them from power spikes. If you put a powered hub between the pojo and the card that would fix this issue if it is actually a power issue.