1 ============================
2 ALSA Jack Software Injection
3 ============================
4
5 Simple Introduction On Jack Injection
6 =====================================
7
8 Here jack injection means users could inject p
9 to the audio jacks through debugfs interface,
10 validate ALSA userspace changes. For example,
11 profile switching code in the pulseaudio, and
12 change works as expected and if the change int
13 in this case, we could inject plugin or plugou
14 jack or to some audio jacks, we don't need to
15 machine and plug/unplug physical devices to th
16
17 In this design, an audio jack doesn't equal to
18 Sometimes a physical audio jack contains multi
19 ALSA driver creates multi ``jack_kctl`` for a
20 ``snd_jack`` represents a physical audio jack
21 represents a function, for example a physical
22 headphone and mic_in, the ALSA ASoC driver wil
23 for this jack. The jack injection is implement
24 ``jack_kctl`` instead of ``snd_jack``.
25
26 To inject events to audio jacks, we need to en
27 via ``sw_inject_enable`` first, once it is ena
28 change the state by hardware events anymore, w
29 plugout events via ``jackin_inject`` and check
30 ``status``, after we finish our test, we need
31 injection via ``sw_inject_enable`` too, once i
32 state will be restored according to the last r
33 and will change by future hardware events.
34
35 The Layout of Jack Injection Interface
36 ======================================
37
38 If users enable the SND_JACK_INJECTION_DEBUG i
39 jack injection interface will be created as be
40 ::
41
42 $debugfs_mount_dir/sound
43 |-- card0
44 |-- |-- HDMI_DP_pcm_10_Jack
45 |-- |-- |-- jackin_inject
46 |-- |-- |-- kctl_id
47 |-- |-- |-- mask_bits
48 |-- |-- |-- status
49 |-- |-- |-- sw_inject_enable
50 |-- |-- |-- type
51 ...
52 |-- |-- HDMI_DP_pcm_9_Jack
53 |-- |-- jackin_inject
54 |-- |-- kctl_id
55 |-- |-- mask_bits
56 |-- |-- status
57 |-- |-- sw_inject_enable
58 |-- |-- type
59 |-- card1
60 |-- HDMI_DP_pcm_5_Jack
61 |-- |-- jackin_inject
62 |-- |-- kctl_id
63 |-- |-- mask_bits
64 |-- |-- status
65 |-- |-- sw_inject_enable
66 |-- |-- type
67 ...
68 |-- Headphone_Jack
69 |-- |-- jackin_inject
70 |-- |-- kctl_id
71 |-- |-- mask_bits
72 |-- |-- status
73 |-- |-- sw_inject_enable
74 |-- |-- type
75 |-- Headset_Mic_Jack
76 |-- jackin_inject
77 |-- kctl_id
78 |-- mask_bits
79 |-- status
80 |-- sw_inject_enable
81 |-- type
82
83 The Explanation Of The Nodes
84 ======================================
85
86 kctl_id
87 read-only, get jack_kctl->kctl's id
88 ::
89
90 sound/card1/Headphone_Jack# cat kctl_id
91 Headphone Jack
92
93 mask_bits
94 read-only, get jack_kctl's supported events
95 ::
96
97 sound/card1/Headphone_Jack# cat mask_bits
98 0x0001 HEADPHONE(0x0001)
99
100 status
101 read-only, get jack_kctl's current status
102
103 - headphone unplugged:
104
105 ::
106
107 sound/card1/Headphone_Jack# cat status
108 Unplugged
109
110 - headphone plugged:
111
112 ::
113
114 sound/card1/Headphone_Jack# cat status
115 Plugged
116
117 type
118 read-only, get snd_jack's supported events f
119 ::
120
121 sound/card1/Headphone_Jack# cat type
122 0x7803 HEADPHONE(0x0001) MICROPHONE(0x000
123
124 sw_inject_enable
125 read-write, enable or disable injection
126
127 - injection disabled:
128
129 ::
130
131 sound/card1/Headphone_Jack# cat sw_inject
132 Jack: Headphone Jack Inject
133
134 - injection enabled:
135
136 ::
137
138 sound/card1/Headphone_Jack# cat sw_inject
139 Jack: Headphone Jack Inject
140
141 - to enable jack injection:
142
143 ::
144
145 sound/card1/Headphone_Jack# echo 1 > sw_i
146
147 - to disable jack injection:
148
149 ::
150
151 sound/card1/Headphone_Jack# echo 0 > sw_i
152
153 jackin_inject
154 write-only, inject plugin or plugout
155
156 - to inject plugin:
157
158 ::
159
160 sound/card1/Headphone_Jack# echo 1 > jack
161
162 - to inject plugout:
163
164 ::
165
166 sound/card1/Headphone_Jack# echo 0 > jack
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