I'm not sure about the point of testing on different hardware ... We have
devices that used to work and now don't. Dragonfly USB DAC is cheap and
easily available.
On Apr 26, 2013 6:35 AM, "Alan Stern" <[email protected]> wrote:

> I didn't see the last few comments until today, because I wasn't
> subscribed to this bug report.  Now I am.
>
> The two usbmon traces don't seem to have any significant differences.
> The problem must lie at a lower level, probably something in the
> hardware.  Is there any way you can try testing the device with a
> different type of computer?
>
> In answer to the questions above:
>
> 1) USB 1.1 devices can be either full speed or low speed.  This device
> is full speed.  (Low-speed USB does not have enough bandwidth for high-
> quality audio and does not support isochronous transfers.)
>
> 2) The two modes do have different bandwidth requirements; both are well
> below the limits of full-speed USB.  For example, the usbmon traces
> showed that the device was using no more than 273 bytes of data every
> millisecond, whereas full-speed USB can transfer over 1000 bytes of
> isochronous data per millisecond.
>
> 3) The buffer size is the same in the working and non-working cases, as
> far as I can tell.
>
> The easiest way for me to work on this may be to buy one of these
> devices for testing here.  Do you know if any of them are available from
> Amazon?
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1136110
>
> Title:
>   USB Audio Codec choppy playback
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1136110/+subscriptions
>

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https://bugs.launchpad.net/bugs/1136110

Title:
  USB Audio Codec choppy playback

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