1 ============================ 1 ============================
2 ALSA Jack Software Injection 2 ALSA Jack Software Injection
3 ============================ 3 ============================
4 4
5 Simple Introduction On Jack Injection 5 Simple Introduction On Jack Injection
6 ===================================== 6 =====================================
7 7
8 Here jack injection means users could inject p 8 Here jack injection means users could inject plugin or plugout events
9 to the audio jacks through debugfs interface, 9 to the audio jacks through debugfs interface, it is helpful to
10 validate ALSA userspace changes. For example, 10 validate ALSA userspace changes. For example, we change the audio
11 profile switching code in the pulseaudio, and 11 profile switching code in the pulseaudio, and we want to verify if the
12 change works as expected and if the change int 12 change works as expected and if the change introduce the regression,
13 in this case, we could inject plugin or plugou 13 in this case, we could inject plugin or plugout events to an audio
14 jack or to some audio jacks, we don't need to 14 jack or to some audio jacks, we don't need to physically access the
15 machine and plug/unplug physical devices to th 15 machine and plug/unplug physical devices to the audio jack.
16 16
17 In this design, an audio jack doesn't equal to 17 In this design, an audio jack doesn't equal to a physical audio jack.
18 Sometimes a physical audio jack contains multi 18 Sometimes a physical audio jack contains multi functions, and the
19 ALSA driver creates multi ``jack_kctl`` for a 19 ALSA driver creates multi ``jack_kctl`` for a ``snd_jack``, here the
20 ``snd_jack`` represents a physical audio jack 20 ``snd_jack`` represents a physical audio jack and the ``jack_kctl``
21 represents a function, for example a physical 21 represents a function, for example a physical jack has two functions:
22 headphone and mic_in, the ALSA ASoC driver wil 22 headphone and mic_in, the ALSA ASoC driver will build 2 ``jack_kctl``
23 for this jack. The jack injection is implement 23 for this jack. The jack injection is implemented based on the
24 ``jack_kctl`` instead of ``snd_jack``. 24 ``jack_kctl`` instead of ``snd_jack``.
25 25
26 To inject events to audio jacks, we need to en 26 To inject events to audio jacks, we need to enable the jack injection
27 via ``sw_inject_enable`` first, once it is ena 27 via ``sw_inject_enable`` first, once it is enabled, this jack will not
28 change the state by hardware events anymore, w 28 change the state by hardware events anymore, we could inject plugin or
29 plugout events via ``jackin_inject`` and check 29 plugout events via ``jackin_inject`` and check the jack state via
30 ``status``, after we finish our test, we need 30 ``status``, after we finish our test, we need to disable the jack
31 injection via ``sw_inject_enable`` too, once i 31 injection via ``sw_inject_enable`` too, once it is disabled, the jack
32 state will be restored according to the last r 32 state will be restored according to the last reported hardware events
33 and will change by future hardware events. 33 and will change by future hardware events.
34 34
35 The Layout of Jack Injection Interface 35 The Layout of Jack Injection Interface
36 ====================================== 36 ======================================
37 37
38 If users enable the SND_JACK_INJECTION_DEBUG i 38 If users enable the SND_JACK_INJECTION_DEBUG in the kernel, the audio
39 jack injection interface will be created as be 39 jack injection interface will be created as below:
40 :: 40 ::
41 41
42 $debugfs_mount_dir/sound 42 $debugfs_mount_dir/sound
43 |-- card0 43 |-- card0
44 |-- |-- HDMI_DP_pcm_10_Jack 44 |-- |-- HDMI_DP_pcm_10_Jack
45 |-- |-- |-- jackin_inject 45 |-- |-- |-- jackin_inject
46 |-- |-- |-- kctl_id 46 |-- |-- |-- kctl_id
47 |-- |-- |-- mask_bits 47 |-- |-- |-- mask_bits
48 |-- |-- |-- status 48 |-- |-- |-- status
49 |-- |-- |-- sw_inject_enable 49 |-- |-- |-- sw_inject_enable
50 |-- |-- |-- type 50 |-- |-- |-- type
51 ... 51 ...
52 |-- |-- HDMI_DP_pcm_9_Jack 52 |-- |-- HDMI_DP_pcm_9_Jack
53 |-- |-- jackin_inject 53 |-- |-- jackin_inject
54 |-- |-- kctl_id 54 |-- |-- kctl_id
55 |-- |-- mask_bits 55 |-- |-- mask_bits
56 |-- |-- status 56 |-- |-- status
57 |-- |-- sw_inject_enable 57 |-- |-- sw_inject_enable
58 |-- |-- type 58 |-- |-- type
59 |-- card1 59 |-- card1
60 |-- HDMI_DP_pcm_5_Jack 60 |-- HDMI_DP_pcm_5_Jack
61 |-- |-- jackin_inject 61 |-- |-- jackin_inject
62 |-- |-- kctl_id 62 |-- |-- kctl_id
63 |-- |-- mask_bits 63 |-- |-- mask_bits
64 |-- |-- status 64 |-- |-- status
65 |-- |-- sw_inject_enable 65 |-- |-- sw_inject_enable
66 |-- |-- type 66 |-- |-- type
67 ... 67 ...
68 |-- Headphone_Jack 68 |-- Headphone_Jack
69 |-- |-- jackin_inject 69 |-- |-- jackin_inject
70 |-- |-- kctl_id 70 |-- |-- kctl_id
71 |-- |-- mask_bits 71 |-- |-- mask_bits
72 |-- |-- status 72 |-- |-- status
73 |-- |-- sw_inject_enable 73 |-- |-- sw_inject_enable
74 |-- |-- type 74 |-- |-- type
75 |-- Headset_Mic_Jack 75 |-- Headset_Mic_Jack
76 |-- jackin_inject 76 |-- jackin_inject
77 |-- kctl_id 77 |-- kctl_id
78 |-- mask_bits 78 |-- mask_bits
79 |-- status 79 |-- status
80 |-- sw_inject_enable 80 |-- sw_inject_enable
81 |-- type 81 |-- type
82 82
83 The Explanation Of The Nodes 83 The Explanation Of The Nodes
84 ====================================== 84 ======================================
85 85
86 kctl_id 86 kctl_id
87 read-only, get jack_kctl->kctl's id 87 read-only, get jack_kctl->kctl's id
88 :: 88 ::
89 89
90 sound/card1/Headphone_Jack# cat kctl_id 90 sound/card1/Headphone_Jack# cat kctl_id
91 Headphone Jack 91 Headphone Jack
92 92
93 mask_bits 93 mask_bits
94 read-only, get jack_kctl's supported events 94 read-only, get jack_kctl's supported events mask_bits
95 :: 95 ::
96 96
97 sound/card1/Headphone_Jack# cat mask_bits 97 sound/card1/Headphone_Jack# cat mask_bits
98 0x0001 HEADPHONE(0x0001) 98 0x0001 HEADPHONE(0x0001)
99 99
100 status 100 status
101 read-only, get jack_kctl's current status 101 read-only, get jack_kctl's current status
102 102
103 - headphone unplugged: 103 - headphone unplugged:
104 104
105 :: 105 ::
106 106
107 sound/card1/Headphone_Jack# cat status 107 sound/card1/Headphone_Jack# cat status
108 Unplugged 108 Unplugged
109 109
110 - headphone plugged: 110 - headphone plugged:
111 111
112 :: 112 ::
113 113
114 sound/card1/Headphone_Jack# cat status 114 sound/card1/Headphone_Jack# cat status
115 Plugged 115 Plugged
116 116
117 type 117 type
118 read-only, get snd_jack's supported events f 118 read-only, get snd_jack's supported events from type (all supported events on the physical audio jack)
119 :: 119 ::
120 120
121 sound/card1/Headphone_Jack# cat type 121 sound/card1/Headphone_Jack# cat type
122 0x7803 HEADPHONE(0x0001) MICROPHONE(0x000 122 0x7803 HEADPHONE(0x0001) MICROPHONE(0x0002) BTN_3(0x0800) BTN_2(0x1000) BTN_1(0x2000) BTN_0(0x4000)
123 123
124 sw_inject_enable 124 sw_inject_enable
125 read-write, enable or disable injection 125 read-write, enable or disable injection
126 126
127 - injection disabled: 127 - injection disabled:
128 128
129 :: 129 ::
130 130
131 sound/card1/Headphone_Jack# cat sw_inject 131 sound/card1/Headphone_Jack# cat sw_inject_enable
132 Jack: Headphone Jack Inject 132 Jack: Headphone Jack Inject Enabled: 0
133 133
134 - injection enabled: 134 - injection enabled:
135 135
136 :: 136 ::
137 137
138 sound/card1/Headphone_Jack# cat sw_inject 138 sound/card1/Headphone_Jack# cat sw_inject_enable
139 Jack: Headphone Jack Inject 139 Jack: Headphone Jack Inject Enabled: 1
140 140
141 - to enable jack injection: 141 - to enable jack injection:
142 142
143 :: 143 ::
144 144
145 sound/card1/Headphone_Jack# echo 1 > sw_i 145 sound/card1/Headphone_Jack# echo 1 > sw_inject_enable
146 146
147 - to disable jack injection: 147 - to disable jack injection:
148 148
149 :: 149 ::
150 150
151 sound/card1/Headphone_Jack# echo 0 > sw_i 151 sound/card1/Headphone_Jack# echo 0 > sw_inject_enable
152 152
153 jackin_inject 153 jackin_inject
154 write-only, inject plugin or plugout 154 write-only, inject plugin or plugout
155 155
156 - to inject plugin: 156 - to inject plugin:
157 157
158 :: 158 ::
159 159
160 sound/card1/Headphone_Jack# echo 1 > jack 160 sound/card1/Headphone_Jack# echo 1 > jackin_inject
161 161
162 - to inject plugout: 162 - to inject plugout:
163 163
164 :: 164 ::
165 165
166 sound/card1/Headphone_Jack# echo 0 > jack 166 sound/card1/Headphone_Jack# echo 0 > jackin_inject
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