From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: [PATCH 1/2] ALSA: include/linux/usb/audio.h: add __attribute__((packed)) Date: Wed, 12 May 2010 08:41:28 +0200 Message-ID: <4BEA4D98.5010900@ladisch.de> References: <1273594430-9356-1-git-send-email-daniel@caiaq.de> <20100511225054.GL30801@buzzloop.caiaq.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out1.smtp.messagingengine.com (out1.smtp.messagingengine.com [66.111.4.25]) by alsa0.perex.cz (Postfix) with ESMTP id A796A24448 for ; Wed, 12 May 2010 08:41:35 +0200 (CEST) In-Reply-To: <20100511225054.GL30801@buzzloop.caiaq.de> 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: Daniel Mack Cc: Takashi Iwai , alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org Daniel Mack wrote: > ... > Thanks! One of the noted TODOs is that UAC2 offers the ability to a > device to dynamically change the supported range of options for a given > control. So an enum-driven control can get new values, lose some, > whatever. What would be the best way to map that to ALSA controls? The control callbacks accept and return the new values; userspace gets notified of the changed control information with snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, &elem_id); I'm quite sure that alsamixer can cope with this, but I don't know about any other mixers. :) I think "alsactl restore" already does the right thing for controls that have changed. > Another thing that we would need to support at some time is clock > selectors to switch from an internal clock to some external one. And > this can also be notfied dynamically - so for example: once an external > S/PDIF transmitter is connected, the driver gets informed about a new > valid clock source. I haven't found anything how this could be passed on > to higher levels from a driver, but I might have missed something :) With a mixer control "Clock Source", of course. :) Or are you talking about new samples rates made available? Regards, Clemens