Re: [Alsa-devel] Problems with Hercules DJ Console and the usb-audio driver
On Thu, 2005-09-15 at 14:13 +0200, Clemens Ladisch wrote:
> Horms wrote:
> > On Wed, Sep 14, 2005 at 03:29:13PM +0200, Daniel Svensson wrote:
> > > CONFIG_USB_BANDWIDTH is enabled by default in the debian kernel. Could
> > > this be changed? According to the alsa developer who helped me debug the
> > > problem with my usb soundcard CONFIG_USB_BANDWIDTH should be disabled.
> > > The original email is forwarded here:
> >
> > That sounds fair enough to me, as long there are no objections
> > from the rest of the kernel-team.
> >
> > Clemens, could you provide a little more information on
> > the problems that CONFIG_USB_BANDWIDTH causes?
>
> The code that implements it computes wrong values for the bandwidth
> utilization. This doesn't seem to matter much for full speed stereo
> devices, but we have several bug reports for multichannel and/or high
> speed devices where usb_submit_urb() incorrectly returns -ENOSPC
> errors.
>
> The comment above the usb_check_bandwidth() function in hcd.c lists
> several of the known bugs.
>
> Perhaps CONFIG_USB_BANDWIDTH should have been marked BROKEN instead of
> just EXPERIMENTAL.
Has this been reported upstream? Possibly the USB maintainers don't
know that this is causing real problems for users.
Lee
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