Hello, I was told to email this to this list... I filed a kernel bug here:

https://bugzilla.kernel.org/show_bug.cgi?id=90101

With the following content:
"I have done extensive testing on this issue, and basically on any kernel 
version higher than or equal to 3.13, I am unable to use my USB Create 
Soundblaster card.  The issue seems related to the USB subsystem as it 
works just fine in the USB3 ports.  I did a kernel bisect between 3.12.0 and 
3.13.0, and the offending commit is 

d0ce5c6b9208c79fc725c578eebdeb5724faf17d
USB: EHCI: use a bandwidth-allocation table

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d0ce5c6b9208c79fc725c578eebdeb5724faf17d

What happens is video playback stutters very heavily and there is no sound 
stream making it out the SPDIF port on the USB soundcard.  I also tried with 
the speaker-test application and get a "Broken pipe" error.  

$ speaker-test -D iec958:CARD=Pro,DEV=0 -c 2 -t wav

speaker-test 1.0.28

Playback device is iec958:CARD=Pro,DEV=0
Stream parameters are 48000Hz, S16_LE, 2 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 96 to 262144
Period size range from 48 to 131072
Using max buffer size 262144
Periods = 4
Unable to set hw params for playback: Broken pipe
Setting of hwparams failed: Broken pipe

If I move to the USB3 port it works as expected, so the issue is most 
definitely on the USB2 side.  

The USB hardware is:
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset 
Family USB Enhanced Host Controller #2 (rev 04)
        Subsystem: Lenovo Device 3086
        Kernel driver in use: ehci-pci


The Soundblaster hardware is: 
Bus 001 Device 004: ID 041e:30df Creative Technology, Ltd"


Thank you for your time.


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