1 =================================
2 Notes on Maya44 USB Audio Support
3 =================================
4
5 .. note::
6 The following is the original document of Rainer's patch that the
7 current maya44 code based on. Some contents might be obsoleted, but I
8 keep here as reference -- tiwai
9
10 Feb 14, 2008
11
12 Rainer Zimmermann <mail@lightshed.de>
13
14 STATE OF DEVELOPMENT
15 ====================
16
17 This driver is being developed on the initiative of Piotr Makowski (oponek@gmail.com) and financed by Lars Bergmann.
18 Development is carried out by Rainer Zimmermann (mail@lightshed.de).
19
20 ESI provided a sample Maya44 card for the development work.
21
22 However, unfortunately it has turned out difficult to get detailed programming information, so I (Rainer Zimmermann) had to find out some card-specific information by experiment and conjecture. Some information (in particular, several GPIO bits) is still missing.
23
24 This is the first testing version of the Maya44 driver released to the alsa-devel mailing list (Feb 5, 2008).
25
26
27 The following functions work, as tested by Rainer Zimmermann and Piotr Makowski:
28
29 - playback and capture at all sampling rates
30 - input/output level
31 - crossmixing
32 - line/mic switch
33 - phantom power switch
34 - analogue monitor a.k.a bypass
35
36
37 The following functions *should* work, but are not fully tested:
38
39 - Channel 3+4 analogue - S/PDIF input switching
40 - S/PDIF output
41 - all inputs/outputs on the M/IO/DIO extension card
42 - internal/external clock selection
43
44
45 *In particular, we would appreciate testing of these functions by anyone who has access to an M/IO/DIO extension card.*
46
47
48 Things that do not seem to work:
49
50 - The level meters ("multi track") in 'alsamixer' do not seem to react to signals in (if this is a bug, it would probably be in the existing ICE1724 code).
51
52 - Ardour 2.1 seems to work only via JACK, not using ALSA directly or via OSS. This still needs to be tracked down.
53
54
55 DRIVER DETAILS
56 ==============
57
58 the following files were added:
59
60 * pci/ice1724/maya44.c - Maya44 specific code
61 * pci/ice1724/maya44.h
62 * pci/ice1724/ice1724.patch
63 * pci/ice1724/ice1724.h.patch - PROPOSED patch to ice1724.h (see SAMPLING RATES)
64 * i2c/other/wm8776.c - low-level access routines for Wolfson WM8776 codecs
65 * include/wm8776.h
66
67
68 Note that the wm8776.c code is meant to be card-independent and does not actually register the codec with the ALSA infrastructure.
69 This is done in maya44.c, mainly because some of the WM8776 controls are used in Maya44-specific ways, and should be named appropriately.
70
71
72 the following files were created in pci/ice1724, simply #including the corresponding file from the alsa-kernel tree:
73
74 * wtm.h
75 * vt1720_mobo.h
76 * revo.h
77 * prodigy192.h
78 * pontis.h
79 * phase.h
80 * maya44.h
81 * juli.h
82 * aureon.h
83 * amp.h
84 * envy24ht.h
85 * se.h
86 * prodigy_hifi.h
87
88
89 *I hope this is the correct way to do things.*
90
91
92 SAMPLING RATES
93 ==============
94
95 The Maya44 card (or more exactly, the Wolfson WM8776 codecs) allow a maximum sampling rate of 192 kHz for playback and 92 kHz for capture.
96
97 As the ICE1724 chip only allows one global sampling rate, this is handled as follows:
98
99 * setting the sampling rate on any open PCM device on the maya44 card will always set the *global* sampling rate for all playback and capture channels.
100
101 * In the current state of the driver, setting rates of up to 192 kHz is permitted even for capture devices.
102
103 *AVOID CAPTURING AT RATES ABOVE 96kHz*, even though it may appear to work. The codec cannot actually capture at such rates, meaning poor quality.
104
105
106 I propose some additional code for limiting the sampling rate when setting on a capture pcm device. However because of the global sampling rate, this logic would be somewhat problematic.
107
108 The proposed code (currently deactivated) is in ice1712.h.patch, ice1724.c and maya44.c (in pci/ice1712).
109
110
111 SOUND DEVICES
112 =============
113
114 PCM devices correspond to inputs/outputs as follows (assuming Maya44 is card #0):
115
116 * hw:0,0 input - stereo, analog input 1+2
117 * hw:0,0 output - stereo, analog output 1+2
118 * hw:0,1 input - stereo, analog input 3+4 OR S/PDIF input
119 * hw:0,1 output - stereo, analog output 3+4 (and SPDIF out)
120
121
122 NAMING OF MIXER CONTROLS
123 ========================
124
125 (for more information about the signal flow, please refer to the block diagram on p.24 of the ESI Maya44 manual, or in the ESI windows software).
126
127
128 PCM
129 (digital) output level for channel 1+2
130 PCM 1
131 same for channel 3+4
132
133 Mic Phantom+48V
134 switch for +48V phantom power for electrostatic microphones on input 1/2.
135
136 Make sure this is not turned on while any other source is connected to input 1/2.
137 It might damage the source and/or the maya44 card.
138
139 Mic/Line input
140 if switch is on, input jack 1/2 is microphone input (mono), otherwise line input (stereo).
141
142 Bypass
143 analogue bypass from ADC input to output for channel 1+2. Same as "Monitor" in the windows driver.
144 Bypass 1
145 same for channel 3+4.
146
147 Crossmix
148 cross-mixer from channels 1+2 to channels 3+4
149 Crossmix 1
150 cross-mixer from channels 3+4 to channels 1+2
151
152 IEC958 Output
153 switch for S/PDIF output.
154
155 This is not supported by the ESI windows driver.
156 S/PDIF should output the same signal as channel 3+4. [untested!]
157
158
159 Digital output selectors
160 These switches allow a direct digital routing from the ADCs to the DACs.
161 Each switch determines where the digital input data to one of the DACs comes from.
162 They are not supported by the ESI windows driver.
163 For normal operation, they should all be set to "PCM out".
164
165 H/W
166 Output source channel 1
167 H/W 1
168 Output source channel 2
169 H/W 2
170 Output source channel 3
171 H/W 3
172 Output source channel 4
173
174 H/W 4 ... H/W 9
175 unknown function, left in to enable testing.
176
177 Possibly some of these control S/PDIF output(s).
178 If these turn out to be unused, they will go away in later driver versions.
179
180 Selectable values for each of the digital output selectors are:
181
182 PCM out
183 DAC output of the corresponding channel (default setting)
184 Input 1 ... Input 4
185 direct routing from ADC output of the selected input channel
186
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