From mboxrd@z Thu Jan 1 00:00:00 1970 From: libin.yang@linux.intel.com Subject: [PATCH v2 1/3] ALSA: Add documentation about HD-audio DP MST Date: Tue, 12 Jan 2016 11:13:25 +0800 Message-ID: <1452568407-20771-2-git-send-email-libin.yang@linux.intel.com> References: <1452568407-20771-1-git-send-email-libin.yang@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by alsa0.perex.cz (Postfix) with ESMTP id 1773026513B for ; Tue, 12 Jan 2016 04:17:05 +0100 (CET) In-Reply-To: <1452568407-20771-1-git-send-email-libin.yang@linux.intel.com> 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: alsa-devel@alsa-project.org, tiwai@suse.de Cc: libin.yang@intel.com, mengdong.lin@intel.com, Libin Yang List-Id: alsa-devel@alsa-project.org From: Libin Yang Add the documentation about HD-audio DP MST: 1. Overview 2. Jack Others will be added later. Signed-off-by: Libin Yang --- Documentation/sound/alsa/HD-Audio-DP-MST-audio.txt | 74 ++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 Documentation/sound/alsa/HD-Audio-DP-MST-audio.txt diff --git a/Documentation/sound/alsa/HD-Audio-DP-MST-audio.txt b/Documentation/sound/alsa/HD-Audio-DP-MST-audio.txt new file mode 100644 index 0000000..82744ac --- /dev/null +++ b/Documentation/sound/alsa/HD-Audio-DP-MST-audio.txt @@ -0,0 +1,74 @@ +To support DP MST audio, HD Audio hdmi codec driver introduces virtual pin +and dynamic pcm assignment. + +Virtual pin is an extension of per_pin. The most difference of DP MST +from legacy is that DP MST introduces device entry. Each pin can contain +several device entries. Each device entry behaves as a pin. + +As each pin may contain several device entries and each codec may contain +several pins, if we use one pcm per per_pin, there will be many PCMs. +The new solution is to create a few PCMs and to dynamically bind pcm to +per_pin. Driver uses spec->dyn_pcm_assign flag to indicate whether to use +the new solution. + +PCM +=== +To be added + + +Jack +==== + +Presume: + - MST must be dyn_pcm_assign, and it is acomp (for Intel scenario); + - NON-MST may or may not be dyn_pcm_assign, it can be acomp or !acomp; + +So there are the following scenarios: + a. MST (&& dyn_pcm_assign && acomp) + b. NON-MST && dyn_pcm_assign && acomp + c. NON-MST && !dyn_pcm_assign && !acomp + +Below discussion will ignore MST and NON-MST difference as it doesn't +impact on jack handling too much. + +Driver uses struct hdmi_pcm pcm[] array in hdmi_spec and snd_jack is +a member of hdmi_pcm. Each pin has one struct hdmi_pcm * pcm pointer. + +For !dyn_pcm_assign, per_pin->pcm will assigned to spec->pcm[n] statically. + +For dyn_pcm_assign, per_pin->pcm will assigned to spec->pcm[n] +when monitor is hotplugged. + + +Build Jack +---------- + +- dyn_pcm_assign +Will not use hda_jack but use snd_jack in spec->pcm_rec[pcm_idx].jack directly. + +- !dyn_pcm_assign +Use hda_jack and assign spec->pcm_rec[pcm_idx].jack = jack->jack statically. + + +Unsolicited Event Enabling +-------------------------- +Enable unsolicited event if !acomp. + + +Monitor Hotplug Event Handling +------------------------------ +- acomp +pin_eld_notify() -> check_presence_and_report() -> hdmi_present_sense() -> +sync_eld_via_acomp(). +Use directly snd_jack_report() on spec->pcm_rec[pcm_idx].jack for +both dyn_pcm_assign and !dyn_pcm_assign + +- !acomp +Hdmi_unsol_event() -> hdmi_intrinsic_event() -> check_presence_and_report() -> +hdmi_present_sense() -> hdmi_prepsent_sense_via_verbs() +Use directly snd_jack_report() on spec->pcm_rec[pcm_idx].jack for dyn_pcm_assign. +Use hda_jack mechanism to handle jack events. + + +Others to be added later +======================== -- 1.9.1