High-bandwidth/multiple transactions per microframe in usb audio?

[Takashi Iwai]

On Sun, 26 Apr 2020 10:55:32 +0200,
Pavel Hofman wrote:
> 
> Dne 25. 04. 20 v 21:50 Alexander Tsoy napsal(a):
> > В Сб, 25/04/2020 в 20:06 +0200, Pavel Hofman пишет:
> > 
> > And I just noticed that USB-audio driver can't properly parse max
> > packet size for SuperSpeed and SuperSpeed+ devices yet. See
> > audio_format_alloc_init().
> 
> Very good catch. IIUC there are two basically equivalent calculations
> for HighSpeed -
> 
> https://elixir.bootlin.com/linux/v5.6.7/source/drivers/usb/core/urb.c#L445
> 
> 
> https://elixir.bootlin.com/linux/v5.6.7/source/sound/usb/stream.c#L691
> 
> 
> And audio_format_alloc_init missing the sections for SS, SS+ in
> usb_submit_urb . Perhpas a common method to make the calculation for all
> cases would make it more robust?

Yes, a common USB helper function sounds like a good idea.


thanks,

Takashi