A:android本身的机制，调节volume时不会去控制声卡上的寄存器，而是通过软件算法将volume调大或者调小。声卡控制的音频输出有好几路，每一路都有vol和gain控制着音量大小。 #cat /sys/class/sound/card0/device/RT5631/codec_reg →察看寄存器值 # tinymix 15 20 → Speaker Playback Volume设置为20 # tinymix 18 20 → HP Playback Volume设置为20 root@android:/# tinymix
Numberof controls: 82
ctl type num name value
0 ENUM 1 MIC1Mode Control Differential
1 INT 1 MIC1Boost 3
2 ENUM 1 MIC2Mode Control Differential
3 INT 1 MIC2Boost 3
4 ENUM 1 MONOINMode Control Differential
5 INT 2 MONOIN_RXCapture Volume 23 23
6 INT 2 AXICapture Volume 23 23
7 INT 2 PCMRecord Volume 255 255
8 BOOL 2 PCMRecord Switch On On
9 INT 2 PCMPlayback Volume 255 255
10 BOOL 2 PCMPlayback Switch On On
11 BOOL 1 AXO1Playback Switch On
12 BOOL 1 AXO2Playback Switch On
13 BOOL 2 OUTVOLChannel Switch On On
14 BOOL 2 SpeakerPlayback Switch On On
15 INT 2 SpeakerPlayback Volume 20 20
16 BOOL 1 MONOPlayback Switch Off
17 BOOL 2 HPPlayback Switch On On
18 INT 2 HPPlayback Volume 31 31
19 BOOL 1 DMICSwitch Off
20 BOOL 2 DMICCapture Switch Off Off
21 ENUM 1 SPKRatio Control 1.44x
22 BOOL 1 CallMode Switch Off
23 ENUM 1 HPRMux Right HPVOL
24 ENUM 1 HPLMux Left HPVOL
25 ENUM 1 MONOMux MONOMIX
26 ENUM 1 SPORMux SPORMIX
27 ENUM 1 SPOLMux SPOLMIX
28 BOOL 1 AXO2MIXMixer MIC1_BST1 Playback Switch Off
29 BOOL 1 AXO2MIXMixer MIC2_BST2 Playback Switch Off
30 BOOL 1 AXO2MIXMixer OUTVOLL Playback Switch Off
31 BOOL 1 AXO2MIXMixer OUTVOLR Playback Switch Off
32 BOOL 1 SPORMIXMixer SPKVOLL Playback Switch Off
33 BOOL 1 SPORMIXMixer SPKVOLR Playback Switch On
34 BOOL 1 MONOMIXMixer OUTVOLL Playback Switch Off
35 BOOL 1 MONOMIXMixer OUTVOLR Playback Switch Off
36 BOOL 1 SPOLMIXMixer SPKVOLL Playback Switch On
37 BOOL 1 SPOLMIXMixer SPKVOLR Playback Switch Off
38 BOOL 1 AXO1MIXMixer MIC1_BST1 Playback Switch Off
39 BOOL 1 AXO1MIXMixer MIC2_BST2 Playback Switch Off
40 BOOL 1 AXO1MIXMixer OUTVOLL Playback Switch On
41 BOOL 1 AXO1MIXMixer OUTVOLR Playback Switch Off
42 ENUM 1 RightSPKVOL Mux SPKMIXR
43 ENUM 1 RightHPVOL Mux OUTMIXR
44 ENUM 1 RightOUTVOL Mux OUTMIXR
45 ENUM 1 LeftOUTVOL Mux OUTMIXL
46 ENUM 1 LeftHPVOL Mux OUTMIXL
47 ENUM 1 LeftSPKVOL Mux SPKMIXL
48 BOOL 1 SPKMIXRMixer OUTMIXR Playback Switch Off
49 BOOL 1 SPKMIXRMixer DACR Playback Switch On
50 BOOL 1 SPKMIXRMixer MIC2_P Playback Switch Off
51 BOOL 1 SPKMIXRMixer RECMIXR Playback Switch Off
52 BOOL 1 OUTMIXRMixer VDAC Playback Switch Off
53 BOOL 1 OUTMIXRMixer AXIRVOL Playback Switch Off
54 BOOL 1 OUTMIXRMixer AXILVOL Playback Switch Off
55 BOOL 1 OUTMIXRMixer MONOIN_RXN Playback Switch Off
56 BOOL 1 OUTMIXRMixer MIC2_BST2 Playback Switch Off
57 BOOL 1 OUTMIXRMixer MIC1_BST1 Playback Switch Off
58 BOOL 1 OUTMIXRMixer DACR Playback Switch On
59 BOOL 1 OUTMIXRMixer RECMIXR Playback Switch Off
60 BOOL 1 OUTMIXRMixer RECMIXL Playback Switch Off
61 BOOL 1 OUTMIXLMixer RECMIXL Playback Switch Off
62 BOOL 1 OUTMIXLMixer RECMIXR Playback Switch Off
63 BOOL 1 OUTMIXLMixer DACL Playback Switch On
64 BOOL 1 OUTMIXLMixer MIC1_BST1 Playback Switch Off
65 BOOL 1 OUTMIXLMixer MIC2_BST2 Playback Switch Off
66 BOOL 1 OUTMIXLMixer MONOIN_RXP Playback Switch Off
67 BOOL 1 OUTMIXLMixer AXILVOL Playback Switch Off
68 BOOL 1 OUTMIXLMixer AXIRVOL Playback Switch Off
69 BOOL 1 OUTMIXLMixer VDAC Playback Switch Off
70 BOOL 1 SPKMIXLMixer RECMIXL Playback Switch Off
71 BOOL 1 SPKMIXLMixer MIC1_P Playback Switch Off
72 BOOL 1 SPKMIXLMixer DACL Playback Switch On
73 BOOL 1 SPKMIXLMixer OUTMIXL Playback Switch Off
74 BOOL 1 RECMIXRMixer MONOIN_RX Capture Switch On
75 BOOL 1 RECMIXRMixer AXIRVOL Capture Switch Off
76 BOOL 1 RECMIXRMixer MIC2_BST2 Capture Switch On
77 BOOL 1 RECMIXRMixer OUTMIXR Capture Switch Off
78 BOOL 1 RECMIXLMixer OUTMIXL Capture Switch Off
79 BOOL 1 RECMIXLMixer MIC1_BST1 Capture Switch On
80 BOOL 1 RECMIXLMixer AXILVOL Capture Switch Off
81 BOOL 1 RECMIXLMixer MONOIN_RX Capture Switch On
