From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: USB audio2.0 status interrupt endpoint Date: Thu, 3 Mar 2016 14:07:52 +0100 Message-ID: <56D83728.9090404@ladisch.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from dehamd003.servertools24.de (dehamd003.servertools24.de [31.47.254.18]) by alsa0.perex.cz (Postfix) with ESMTP id 75F03260535 for ; Thu, 3 Mar 2016 14:07:54 +0100 (CET) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Puneet Sharma , alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org Puneet Sharma wrote: > As per my understanding, when the above interrupt endpoint is transferred > to host in response to Interrupt IN request, the host should send me a GET > CUR volume class-specific request to further qualify the cause of interrupt. > > However, I am not getting any class-specific request from host in response > to the status interrupt transferred to host. > > My query is do i need to implement a mixer interface in the uac2 kernel > driver to get the request or i am doing something wrong in the process. You must not send a notification for a unit ID that does not exist, so you must implement the mixer interface. And you will get a request to read the control's current volume only if some application that cares about the value (e.g., alsamixer) actually happens to be running on the host. Regards, Clemens