sound/cards/cmipci.rst

2 Brief Notes on C-Media 8338/8738/8768/8770 Driver
8 Front/Rear Multi-channel Playback
9 ---------------------------------
13 DACs, both streams are handled independently unlike the 4/6ch multi-
22 - The first DAC supports U8 and S16LE formats, while the second DAC
23   supports only S16LE.
24 - The second DAC supports only two channel stereo.
27 rate but only fixed rates: 5512, 8000, 11025, 16000, 22050, 32000,
30 The rear output can be heard only when "Four Channel Mode" switch is
35   When "Four Channel Mode" switch is off, the output from rear speakers
42   Well.. I once got the output with correct volume (i.e. same with the
49 If your card has an extra output jack for the rear output, the rear
51 control switch in the driver "Line-In As Rear", which you can change
52 via alsamixer or somewhat else.  When this switch is on, line-in jack
53 is used as rear output.
55 There are two more controls regarding to the rear output.
57 routes, i.e. the 2nd DAC is output from front output.
60 4/6 Multi-Channel Playback
61 --------------------------
63 The recent CM8738 chips support for the 4/6 multi-channel playback
66 When the multi-channel is supported, the driver name has a suffix
67 "-MC" such like "CMI8738-MC6".  You can check this name from
70 When the 4/6-ch output is enabled, the second DAC accepts up to 6 (or
72 formats, the 4/6-ch playback supports only the same condition for all
73 channels.  Since the multi-channel playback mode uses both DACs, you
74 cannot operate with full-duplex.
77 in alsa-lib.  For example, you can play a WAV file with 6 channels like
80 	% aplay -Dsurround51 sixchannels.wav
96 Line-In Mode
97 	an enum control to change the behavior of line-in
98 	jack.  Either "Line-In", "Rear Output" or "Bass Output" can
99 	be selected.  The last item is available only with model 039
101 	When "Rear Output" is chosen, the surround channels 3 and 4
102 	are output to line-in jack.
103 Mic-In Mode
104 	an enum control to change the behavior of mic-in
105 	jack.  Either "Mic-In" or "Center/LFE Output" can be
107 	When "Center/LFE Output" is chosen, the center and bass
108 	channels (channels 5 and 6) are output to mic-in jack.
111 -----------
122 	% aplay -Dhw:0,2 foo.wav
128 	% aplay -Dspdif foo.wav
136 To enable SPDIF output, you need to turn on "IEC958 Output Switch"
138 so-called S/PDIF).  Then you'll see the red light on from the card so
141 from line-out with "IEC958 In Monitor" switch at any time (see
145 but SPDIF is enabled only when the proper format (S16LE), sample rate
147 off.  (Also don't forget to turn on "IEC958 Output Switch", too.)
153 	Mix analog PCM playback and FM-OPL/3 streams and
154 	output through SPDIF.  This switch appears only on old chip
157 	Note: without this control you can output PCM to SPDIF.
158 	This is "mixing" of streams, so e.g. it's not for AC3 output
162 	Select SPDIF input, the internal CD-in (false)
167 	output (aka bypass)
175 	configuration with hardware dip-switch.
187 Note: When "PCM Playback Switch" is on, you'll hear the digital output
188 stream through analog line-out.
191 The AC3 (RAW DIGITAL) OUTPUT
192 ----------------------------
196 access it via alsa-lib.  See alsa-lib documents for more details.
199 turned off so that non-audio data is heard from the analog line-out.
205 the alsa-lib.  If you need to bypass the software conversion of IEC958
211 ----------------------
219 - PCM playback switch
220 - PCM capture switch (to capture the data sent to DAC)
221 - Mic Boost switch
222 - Mic capture volume
223 - Aux playback volume/switch and capture switch
224 - 3D control switch
228 ---------------
230 With CMI8338 chips, the MPU401-UART interface is disabled as default.
246 --------------
248 The FM OPL/3 is also enabled as default only for the first card.
251 The output quality of FM OPL/3 is, however, very weird.
258 ------------------
261 joystick_port=1 module option.  The value 1 means the auto-detection.
262 If the auto-detection fails, try to pass the exact I/O address.
268 ---------------------
272 output of this proc file together with the bug report.