1 =======================
2 HD-Audio DP-MST Support
3 =======================
4
5 To support DP MST audio, HD Audio hdmi codec d
6 and dynamic pcm assignment.
7
8 Virtual pin is an extension of per_pin. The mo
9 from legacy is that DP MST introduces device e
10 several device entries. Each device entry beha
11
12 As each pin may contain several device entries
13 several pins, if we use one pcm per per_pin, t
14 The new solution is to create a few PCMs and t
15 per_pin. Driver uses spec->dyn_pcm_assign flag
16 the new solution.
17
18 PCM
19 ===
20 To be added
21
22 Pin Initialization
23 ==================
24 Each pin may have several device entries (virt
25 the device entries number is dynamically chang
26 it is in DP MST mode, and the device entries n
27 device entries number is 1.
28
29 To simplify the implementation, all the device
30 when bootup no matter whether it is in DP MST
31
32 Connection list
33 ===============
34 DP MST reuses connection list code. The code c
35 device entries on the same pin have the same c
36
37 This means DP MST gets the device entry connec
38 device entry setting.
39
40 Jack
41 ====
42
43 Presume:
44 - MST must be dyn_pcm_assign, and it is acomp
45 - NON-MST may or may not be dyn_pcm_assign, i
46
47 So there are the following scenarios:
48 a. MST (&& dyn_pcm_assign && acomp)
49 b. NON-MST && dyn_pcm_assign && acomp
50 c. NON-MST && !dyn_pcm_assign && !acomp
51
52 Below discussion will ignore MST and NON-MST d
53 impact on jack handling too much.
54
55 Driver uses struct hdmi_pcm pcm[] array in hdm
56 a member of hdmi_pcm. Each pin has one struct
57
58 For !dyn_pcm_assign, per_pin->pcm will assigne
59
60 For dyn_pcm_assign, per_pin->pcm will assigned
61 when monitor is hotplugged.
62
63
64 Build Jack
65 ----------
66
67 - dyn_pcm_assign
68
69 Will not use hda_jack but use snd_jack in sp
70
71 - !dyn_pcm_assign
72
73 Use hda_jack and assign spec->pcm_rec[pcm_id
74
75
76 Unsolicited Event Enabling
77 --------------------------
78 Enable unsolicited event if !acomp.
79
80
81 Monitor Hotplug Event Handling
82 ------------------------------
83 - acomp
84
85 pin_eld_notify() -> check_presence_and_repor
86 sync_eld_via_acomp().
87
88 Use directly snd_jack_report() on spec->pcm_
89 both dyn_pcm_assign and !dyn_pcm_assign
90
91 - !acomp
92
93 hdmi_unsol_event() -> hdmi_intrinsic_event()
94 hdmi_present_sense() -> hdmi_prepsent_sense_
95
96 Use directly snd_jack_report() on spec->pcm_
97 Use hda_jack mechanism to handle jack events
98
99
100 Others to be added later
101 ========================
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