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From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: "Gopal, Saranya" <saranya.gopal@intel.com>,
	Takashi Iwai <tiwai@suse.de>, Con Kolivas <kernel@kolivas.org>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"felipe.balbi@linux.intel.com" <felipe.balbi@linux.intel.com>
Subject: Re: [alsa-devel] ALSA:usb audio Higher sample rates on usb audio no longer working.
Date: Fri, 4 Jan 2019 11:13:29 -0600	[thread overview]
Message-ID: <51872184-3de0-6e69-60e3-c3b4898dcdfa@linux.intel.com> (raw)
In-Reply-To: <C672AA6DAAC36042A98BAD0B0B25BDA94CB021CE@BGSMSX104.gar.corp.intel.com>


On 1/4/19 10:52 AM, Gopal, Saranya wrote:
>>> [ Adding linux-usb ML to Cc, as it's a core USB issue ]
>>>
>>> So the device seems incorrectly advertising as if it were supporting
>>> UAC3 -- assuming the device is still not UAC3-capable.
>>>
>>> IOW, it's a buggy firmware.  We need some blacklisting, or revert the
>>> commit for now, unless any real UAC3 device comes up to the market.
>> IIRC an UAC3-capable device is required to expose a backwards-compatible
>> configuration (either UAC1 or UAC2). Maybe an additional test can be
>> done to harden the detection so that UAC3 is only chosen if indeed a
>> second audio configuration is present as well.
>>
>> I also vaguely recall there was talk about adding information in the BOS
>> descriptor, but I don't know if this was ever published.
>>
>> -Pierre
> The current detection logic is that UAC3 configuration is chosen only when a device has a configuration with audio interface supporting UAC3 protocol.
> Additionally, it already makes sure that UAC3 is selected only when there is more than one configuration.
What I meant if that the other configurations are not checked for UAC1 
or UAC2 capabilities, you only check that there is more than one 
configuration

  reply	other threads:[~2019-01-04 17:13 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-03 11:43 ALSA:usb audio Higher sample rates on usb audio no longer working Con Kolivas
2019-01-03 13:23 ` Takashi Iwai
2019-01-03 23:16   ` Con Kolivas
2019-01-04  6:27     ` Takashi Iwai
2019-01-04 15:23       ` [alsa-devel] " Pierre-Louis Bossart
2019-01-04 16:52         ` Gopal, Saranya
2019-01-04 17:13           ` Pierre-Louis Bossart [this message]
2019-01-04 20:34           ` Con Kolivas
2019-01-05 14:14             ` Gopal, Saranya
2019-01-05 14:02     ` [PATCH] usbcore: Select only first configuration for non-UAC3 compliant devices saranya.gopal
2019-01-05 14:35       ` Greg KH
2019-01-05 17:39     ` [PATCH V2] " saranya.gopal
2019-01-05 22:02       ` Con Kolivas
2019-01-06  2:44     ` [PATCH V3] " saranya.gopal

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