Re: USB low-speed bulk transfers

Steinar H. Gunderson wrote:
> On Thu, Jun 07, 2007 at 01:14:45PM +0200, Clemens Ladisch wrote:
> > Try the attached patch.
> 
> It seems to work well, at least in my limited tests. I've been using it
> together with this patch to make usbaudio.c understand low-speed devices:
> 
> diff -ur linux-2.6.22-rc4/sound/usb/usbaudio.c linux-2.6.22-rc4.patched/sound/usb/usbaudio.c
> --- linux-2.6.22-rc4/sound/usb/usbaudio.c       2007-06-05 02:57:25.000000000 +0200
> +++ linux-2.6.22-rc4.patched/sound/usb/usbaudio.c       2007-06-07 13:56:08.000000000 +0200
>         
>         /* calculate the frequency in 16.16 format */
> -       if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
> -               subs->freqn = get_usb_full_speed_rate(rate);
> -       else        
> +       if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH)
>                 subs->freqn = get_usb_high_speed_rate(rate);
> +       else    
> +               subs->freqn = get_usb_full_speed_rate(rate);

Low speed iso transfers are not possible (and this time we mean it :-) ,
so these changes for the PCM code are not needed.

We still need a check to prevent using an audio streaming interface of
a low speed device.


Regards,
Clemens

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