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From: Takashi Iwai <tiwai@suse.de>
To: Pavel Hofman <pavel.hofman@ivitera.com>
Cc: Alexander Tsoy <alexander@tsoy.me>,
	"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>
Subject: Re: High-bandwidth/multiple transactions per microframe in usb audio?
Date: Mon, 27 Apr 2020 16:05:37 +0200	[thread overview]
Message-ID: <s5hv9llnhvy.wl-tiwai@suse.de> (raw)
In-Reply-To: <dbaba3f0-88b8-21f2-b7dc-5e1c5fadc675@ivitera.com>

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

      reply	other threads:[~2020-04-27 14:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-24  9:42 High-bandwidth/multiple transactions per microframe in usb audio? Pavel Hofman
2020-04-25 12:06 ` Alexander Tsoy
2020-04-25 18:06   ` Pavel Hofman
2020-04-25 19:50     ` Alexander Tsoy
2020-04-26  8:55       ` Pavel Hofman
2020-04-27 14:05         ` Takashi Iwai [this message]

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