From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Pierre-Louis Bossart" Subject: Re: ALSA: hda: hdmi: Hint matching between input devices and pcm devices Date: Tue, 30 Aug 2011 08:01:50 -0500 Message-ID: <21828.806345775$1314709327@news.gmane.org> References: <4E53C32E.9020801@canonical.com> <74CDBE0F657A3D45AFBB94109FB122FF04B24A3823@HQMAIL01.nvidia.com> <4E5483CD.6070808@canonical.com> <74CDBE0F657A3D45AFBB94109FB122FF04B24A3C9E@HQMAIL01.nvidia.com> <4E55F634.9070601@canonical.com> <74CDBE0F657A3D45AFBB94109FB122FF04B24A3E7D@HQMAIL01.nvidia.com> <4E56C088.6080402@canonical.com> <1314656063.27660.9.camel@plb-Dell> <4E5C93E7.9010804@ladisch.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by alsa0.perex.cz (Postfix) with ESMTP id 45D8124466 for ; Tue, 30 Aug 2011 15:01:55 +0200 (CEST) In-Reply-To: <4E5C93E7.9010804@ladisch.de> Content-Language: en-us 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: 'Clemens Ladisch' Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org Hi Clemens, > If the driver can detect ELD changes, it must inform userspace that > the control has changed. If there is no ELD, the _get callback should > return an error, and the control should have been set to unreadable. Bear with my ignorance of controls, but how does the driver 'inform userspace that the control has changed'? > > Or is there a way to link a control to a specify PCM device? > > Yes: set .iface to _PCM instead of _MIXER (this will also prevent > 'normal' mixers from showing this control, but a _BYTE control wouldn't > be shown anyway), and set .device (and .subdevice, if appropriate) to > the PCM device's (sub)device number. This is exactly what I wanted, it makes things simpler. Thanks for the explanation. -Pierre