1 To support DP MST audio, HD Audio hdmi codec driver introduces virtual pin
2 and dynamic pcm assignment.
4 Virtual pin is an extension of per_pin. The most difference of DP MST
5 from legacy is that DP MST introduces device entry. Each pin can contain
6 several device entries. Each device entry behaves as a pin.
8 As each pin may contain several device entries and each codec may contain
9 several pins, if we use one pcm per per_pin, there will be many PCMs.
10 The new solution is to create a few PCMs and to dynamically bind pcm to
11 per_pin. Driver uses spec->dyn_pcm_assign flag to indicate whether to use
23 - MST must be dyn_pcm_assign, and it is acomp (for Intel scenario);
24 - NON-MST may or may not be dyn_pcm_assign, it can be acomp or !acomp;
26 So there are the following scenarios:
27 a. MST (&& dyn_pcm_assign && acomp)
28 b. NON-MST && dyn_pcm_assign && acomp
29 c. NON-MST && !dyn_pcm_assign && !acomp
31 Below discussion will ignore MST and NON-MST difference as it doesn't
32 impact on jack handling too much.
34 Driver uses struct hdmi_pcm pcm[] array in hdmi_spec and snd_jack is
35 a member of hdmi_pcm. Each pin has one struct hdmi_pcm * pcm pointer.
37 For !dyn_pcm_assign, per_pin->pcm will assigned to spec->pcm[n] statically.
39 For dyn_pcm_assign, per_pin->pcm will assigned to spec->pcm[n]
40 when monitor is hotplugged.
47 Will not use hda_jack but use snd_jack in spec->pcm_rec[pcm_idx].jack directly.
50 Use hda_jack and assign spec->pcm_rec[pcm_idx].jack = jack->jack statically.
53 Unsolicited Event Enabling
54 --------------------------
55 Enable unsolicited event if !acomp.
58 Monitor Hotplug Event Handling
59 ------------------------------
61 pin_eld_notify() -> check_presence_and_report() -> hdmi_present_sense() ->
63 Use directly snd_jack_report() on spec->pcm_rec[pcm_idx].jack for
64 both dyn_pcm_assign and !dyn_pcm_assign
67 Hdmi_unsol_event() -> hdmi_intrinsic_event() -> check_presence_and_report() ->
68 hdmi_present_sense() -> hdmi_prepsent_sense_via_verbs()
69 Use directly snd_jack_report() on spec->pcm_rec[pcm_idx].jack for dyn_pcm_assign.
70 Use hda_jack mechanism to handle jack events.
73 Others to be added later
74 ========================