From: Clemens Ladisch <clemens@ladisch.de>
To: Rolf Meeser <rolfm_9dq@yahoo.de>
Cc: Takashi Iwai <tiwai@suse.de>, alsa-devel@alsa-project.org
Subject: Re: [PATCH] snd-usb-audio with multiple audio functions
Date: Mon, 06 Jun 2011 17:47:04 +0200 [thread overview]
Message-ID: <4DECF678.4090808@ladisch.de> (raw)
In-Reply-To: <4DECC12F.60101@yahoo.de>
Rolf Meeser wrote:
> On 06/06/2011 01:44 PM, Clemens Ladisch wrote:
> > Many audio devices with multiple vendor-specific interfaces do not have
> > a control interface. This code would split them into multiple cards.
>
> Breaking existing setups would indeed be bad.
> Are that cards with audio interfaces not following the Audio Class spec?
Yes.
> What would be the easiest way to identify them, so we could assign a new
> card index only in case of a compliant card?
Non-compliant devices don't have a control interface.
In theory, the USB core probes a device's interfaces in order, so the
control interface usually is probed first. However, I'm not sure if
this is really true for all devices. It's probably safest to check
explicitly if the device has any interface marked as audio control 1/2.
Regards,
Clemens
prev parent reply other threads:[~2011-06-06 15:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-06 6:49 [PATCH] snd-usb-audio with multiple audio functions Rolf Meeser
2011-06-06 8:45 ` Daniel Mack
2011-06-06 9:08 ` Takashi Iwai
2011-06-06 15:17 ` Rolf Meeser
2011-06-06 11:44 ` Clemens Ladisch
[not found] ` <4DECC12F.60101@yahoo.de>
2011-06-06 15:47 ` Clemens Ladisch [this message]
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