Re: [Alsa-user] Logitech Z-5 speakers not reliably recognized with CONFIG_HZ>100

[Daniel M. <zo...@gm...>]

On 05.02.2013 23:34, Martin Topholm wrote:
> I'm having an issue with unrealiable probing of my Logitech Z-5 USB
> speakers.
> 
> With Arch Linux (kernel 3.7.5-1-ARCH) the mixer usually gets attached,
> but the audio output interface doesn't (aplay -l list is empty). Building
> a custom kernel with CONFIG_HZ=100 "fixes" the problem and both mixer
> and audio output interface are reliably recognized every time.

That's really strange and I doubt this is realted to CONFIG_HZ really.
Are you totally sure about that?

> alsa-info for 3.7.5-1-ARCH is located at
> http://www.alsa-project.org/db/?f=6ac3bf30b27c6dbe4917b09a677bf695761d5eff
> 
> alsa-info for 3.7.5-1-MPH is located at
> http://www.alsa-project.org/db/?f=df0e3b5db470b86844c0c714c83bcde71f4da90e
> 
> I originally encountered this problem with Ubuntu, when they changed
> from CONFIG_HZ=100 to CONFIG_HZ=250 (I think it happened sometime between
> Natty and Precise). In Ubuntu the speakers could sometimes connect if
> I repeatedly unloaded/loaded snd_usb_audio and removed re-attached
> the speakers. Each time it failed dmesg showed:
> 
>     [   11.568216] cannot find UAC_HEADER
>     [   11.568230] snd-usb-audio: probe of 4-2:1.0 failed with error -5

Which tells you the descriptors of your device is broken. But that
should reliably fail, not just occasionally. And also not depending on
CONFIG_HZ.

Can you please send the output of 'lsusb -v'?


Daniel