From mboxrd@z Thu Jan 1 00:00:00 1970 From: Omari Stephens Subject: Re: [PATCH] New quirk for USB DAC 08bb:2704 Date: Mon, 14 Feb 2011 21:16:18 +0000 Message-ID: <4D599BA2.3040105@xsdg.org> References: <4D570F65.6000108@xsdg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from ocaml.xvm.mit.edu (SIPB-VM-99.MIT.EDU [18.181.0.178]) by alsa0.perex.cz (Postfix) with ESMTP id 1405F103831 for ; Mon, 14 Feb 2011 22:17:46 +0100 (CET) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Takashi Iwai Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On 02/14/2011 05:10 PM, Takashi Iwai wrote: > At Sat, 12 Feb 2011 22:53:25 +0000, > Omari Stephens wrote: >> >> Howdy, all >> >> I have one of these: >> http://www.chordelectronics.co.uk/products_detail.asp?id=63 >> >> It's got one of these USB DACs inside >> ID 08bb:2704 Texas Instruments Japan >> >> The DAC has a single mixer control, Master, which allows you to adjust >> volume and mute/unmute. The fun thing is that the volume adjustment has >> no effect whatsoever. On machines running pulse, this means that output >> will be at 0dB pretty much all the time. (Of course, this is true of >> non-pulse machines also). >> >> The attached patch disables the Master control, which causes pulse to >> control levels entirely in software, as it should for this device. >> >> The main downside to this patch is that, while the volume part of the >> Master control is non-functional, the mute/unmute aspect does work as >> expected. I couldn't figure out how to change the Master control to >> just a mute/unmute control, but if someone has suggestions on what to >> do, that'd be appreciated. Judging by the comments in the code (and >> contrary to what I wrote in the map comment), I presume the mute/unmute >> control is the only reason why 08bb:2702 isn't doing this same thing. > > The patch looks good to me. Could you give your sign-off? Oops; sorry (haven't submitted a kernel patch before). Will do. That said, I have some friends with the same device, and at least one says that the volume control works fine for him, so I want to do a bit more investigation before this quirk gets added. Will send email when I get things figured out a little more. --xsdg