From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: DP1.2 MST audio support discussion Date: Wed, 14 Oct 2015 08:44:14 +0200 Message-ID: References: <96A12704CE18D347B625EE2D4A099D1974C250@SHSMSX103.ccr.corp.intel.com> <561CA911.7070405@canonical.com> <96A12704CE18D347B625EE2D4A099D1974C304@SHSMSX103.ccr.corp.intel.com> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id 4E77F265DF9 for ; Wed, 14 Oct 2015 08:44:15 +0200 (CEST) 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: Raymond Yau Cc: "Yang, Libin" , ALSA Development Mailing List , "airlied@linux.ie" , "Lin, Mengdong" , "Girdwood, Liam R" , "tanuk@iki.fi" , David Henningsson List-Id: alsa-devel@alsa-project.org On Wed, 14 Oct 2015 01:52:08 +0200, Raymond Yau wrote: > > > > > > > > One could then allocate two extra PCMs from the start (9 and 10) to > > > > try > > > > in case the other PCM is busy (my preference), or one could steal one > > > > of > > > > the existing non-busy ones (Takashi's preference). > > > > > > We will create the PCMs based on converter. This means we will > > > create 3 PCMs. And it will not support dynamically allocating PCM. > > > As there are only 3 converters, no more PCMs will be supported. > > > Each PCM will use one converter. If 3 PCMs are all used, connecting > > > monitor will not create new PCM. > > > > > > Yes, if we are not using the PCM, we can re-assign the PCM to another > > > monitor. Currently, user can't decide which PCM is used for which > > > monitor. Image the scenario PCM 3 is assigned to monitor 1, PCM 7 is > > > assigned to monitor 2, PCM 8 is assigned to monitor 3. Monitor 4 is > > > connected, no PCM is available, and driver don't know whether it > > > should steal one PCM for the monitor 4 and user can't change the > > > mapping currently. > > > > Actually, there are a few things to implement properly: > > > > 1. The plug/unplug events are triggered at the actual graphics output > > switching via xrandr or such, not at the time the monitor is > > physically plugged/unplugged. > > > > 2. At switching, the unplug event must be handled at first, and then > > the plug event. > > > > 3. At unplug, detach per_pin object properly from PCM. > > We currently just notify it via jack ctl, and doesn't care the > > rest. Ideally, we should force to stop the PCM and detach > > internally from the assigned pin. > > > > 4. At plug, assign the monitor to the free per_pin object. > > > > So what we've discussed is about the last step; how to map the new > > monitor to per_pin object. This requires the other steps beforehand > > which assures a free per_pin is present at plug time. > > > > Do it mean that only one DP MST port and no HDMI port on the same graphic > card ? No. > If DP MST are dasiy chained, the unplug of the first monitor from Display > Port will cause all DP monitor in the dasiy chain disconnect Yes. Takashi