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Linus Torvalds1da177e2005-04-16 15:20:36 -07001Support for the OPTi 82C931 chip
2--------------------------------
3Note: parts of this README file apply also to other
4cards that use the mad16 driver.
5
6Some items in this README file are based on features
7added to the sound driver after Linux-2.1.91 was out.
8By the time of writing this I do not know which official
9kernel release will include these features.
10Please do not report inconsistencies on older Linux
11kernels.
12
13The OPTi 82C931 is supported in its non-PnP mode.
14Usually you do not need to set jumpers, etc. The sound driver
15will check the card status and if it is required it will
16force the card into a mode in which it can be programmed.
17
18If you have another OS installed on your computer it is recommended
19that Linux and the other OS use the same resources.
20
21Also, it is recommended that resources specified in /etc/modprobe.conf
22and resources specified in /etc/isapnp.conf agree.
23
24Compiling the sound driver
25--------------------------
26I highly recommend that you build a modularized sound driver.
27This document does not cover a sound-driver which is built in
28the kernel.
29
30Sound card support should be enabled as a module (chose m).
31Answer 'm' for these items:
32 Generic OPL2/OPL3 FM synthesizer support (CONFIG_SOUND_ADLIB)
33 Microsoft Sound System support (CONFIG_SOUND_MSS)
34 Support for OPTi MAD16 and/or Mozart based cards (CONFIG_SOUND_MAD16)
35 FM synthesizer (YM3812/OPL-3) support (CONFIG_SOUND_YM3812)
36
37The configuration menu may ask for addresses, IRQ lines or DMA
38channels. If the card is used as a module the module loading
39options will override these values.
40
41For the OPTi 931 you can answer 'n' to:
42 Support MIDI in older MAD16 based cards (requires SB) (CONFIG_SOUND_MAD16_OLDCARD)
43If you do need MIDI support in a Mozart or C928 based card you
44need to answer 'm' to the above question. In that case you will
45also need to answer 'm' to:
46 '100% Sound Blaster compatibles (SB16/32/64, ESS, Jazz16) support' (CONFIG_SOUND_SB)
47
48Go on and compile your kernel and modules. Install the modules. Run depmod -a.
49
50Using isapnptools
51-----------------
52In most systems with a PnP BIOS you do not need to use isapnp. The
53initialization provided by the BIOS is sufficient for the driver
54to pick up the card and continue initialization.
55
56If that fails, or if you have other PnP cards, you need to use isapnp
57to initialize the card.
58This was tested with isapnptools-1.11 but I recommend that you use
59isapnptools-1.13 (or newer). Run pnpdump to dump the information
60about your PnP cards. Then edit the resulting file and select
61the options of your choice. This file is normally installed as
62/etc/isapnp.conf.
63
64The driver has one limitation with respect to I/O port resources:
65IO3 base must be 0x0E0C. Although isapnp allows other ports, this
66address is hard-coded into the driver.
67
68Using kmod and autoloading the sound driver
69-------------------------------------------
70Comment: as of linux-2.1.90 kmod is replacing kerneld.
71The config file '/etc/modprobe.conf' is used as before.
72
73This is the sound part of my /etc/modprobe.conf file.
74Following that I will explain each line.
75
76alias mixer0 mad16
77alias audio0 mad16
78alias midi0 mad16
79alias synth0 opl3
80options sb mad16=1
81options mad16 irq=10 dma=0 dma16=1 io=0x530 joystick=1 cdtype=0
82options opl3 io=0x388
83install mad16 /sbin/modprobe -i mad16 && /sbin/ad1848_mixer_reroute 14 8 15 3 16 6
84
85If you have an MPU daughtercard or onboard MPU you will want to add to the
86"options mad16" line - eg
87
88options mad16 irq=5 dma=0 dma16=3 io=0x530 mpu_io=0x330 mpu_irq=9
89
90To set the I/O and IRQ of the MPU.
91
92
93Explain:
94
95alias mixer0 mad16
96alias audio0 mad16
97alias midi0 mad16
98alias synth0 opl3
99
100When any sound device is opened the kernel requests auto-loading
101of char-major-14. There is a built-in alias that translates this
102request to loading the main sound module.
103
104The sound module in its turn will request loading of a sub-driver
105for mixer, audio, midi or synthesizer device. The first 3 are
106supported by the mad16 driver. The synth device is supported
107by the opl3 driver.
108
109There is currently no way to autoload the sound device driver
110if more than one card is installed.
111
112options sb mad16=1
113
114This is left for historical reasons. If you enable the
115config option 'Support MIDI in older MAD16 based cards (requires SB)'
116or if you use an older mad16 driver it will force loading of the
117SoundBlaster driver. This option tells the SB driver not to look
118for a SB card but to wait for the mad16 driver.
119
120options mad16 irq=10 dma=0 dma16=1 io=0x530 joystick=1 cdtype=0
121options opl3 io=0x388
122
123post-install mad16 /sbin/ad1848_mixer_reroute 14 8 15 3 16 6
124
125This sets resources and options for the mad16 and opl3 drivers.
126I use two DMA channels (only one is required) to enable full duplex.
127joystick=1 enables the joystick port. cdtype=0 disables the cd port.
128You can also set mpu_io and mpu_irq in the mad16 options for the
129uart401 driver.
130
131This tells modprobe to run /sbin/ad1848_mixer_reroute after
132mad16 is successfully loaded and initialized. The source
133for ad1848_mixer_reroute is appended to the end of this readme
134file. It is impossible for the sound driver to know the actual
135connections to the mixer. The 3 inputs intended for cd, synth
136and line-in are mapped to the generic inputs line1, line2 and
137line3. This program reroutes these mixer channels to their
138right names (note the right mapping depends on the actual sound
139card that you use).
140The numeric parameters mean:
141 14=line1 8=cd - reroute line1 to the CD input.
142 15=line2 3=synth - reroute line2 to the synthesizer input.
143 16=line3 6=line - reroute line3 to the line input.
144For reference on other input names look at the file
145/usr/include/linux/soundcard.h.
146
147Using a joystick
148-----------------
149You must enable a joystick in the mad16 options. (also
150in /etc/isapnp.conf if you use it).
151Tested with regular analog joysticks.
152
153A CDROM drive connected to the sound card
154-----------------------------------------
155The 82C931 chip has support only for secondary ATAPI cdrom.
156(cdtype=8). Loading the mad16 driver resets the C931 chip
157and if a cdrom was already mounted it may cause a complete
158system hang. Do not use the sound card if you have an alternative.
159If you do use the sound card it is important that you load
160the mad16 driver (use "modprobe mad16" to prevent auto-unloading)
161before the cdrom is accessed the first time.
162
163Using the sound driver built-in to the kernel may help here, but...
164Most new systems have a PnP BIOS and also two IDE controllers.
165The IDE controller on the sound card may be needed only on older
166systems (which have only one IDE controller) but these systems
167also do not have a PnP BIOS - requiring isapnptools and a modularized
168driver.
169
170Known problems
171--------------
1721. See the section on "A CDROM drive connected to the sound card".
173
1742. On my system the codec cannot capture companded sound samples.
175 (eg., recording from /dev/audio). When any companded capture is
176 requested I get stereo-16 bit samples instead. Playback of
177 companded samples works well. Apparently this problem is not common
178 to all C931 based cards. I do not know how to identify cards that
179 have this problem.
180
181Source for ad1848_mixer_reroute.c
182---------------------------------
183#include <stdio.h>
184#include <fcntl.h>
185#include <linux/soundcard.h>
186
187static char *mixer_names[SOUND_MIXER_NRDEVICES] =
188 SOUND_DEVICE_LABELS;
189
190int
191main(int argc, char **argv) {
192 int val, from, to;
193 int i, fd;
194
195 fd = open("/dev/mixer", O_RDWR);
196 if(fd < 0) {
197 perror("/dev/mixer");
198 return 1;
199 }
200
201 for(i = 2; i < argc; i += 2) {
202 from = atoi(argv[i-1]);
203 to = atoi(argv[i]);
204
205 if(to == SOUND_MIXER_NONE)
206 fprintf(stderr, "%s: turning off mixer %s\n",
207 argv[0], mixer_names[to]);
208 else
209 fprintf(stderr, "%s: rerouting mixer %s to %s\n",
210 argv[0], mixer_names[from], mixer_names[to]);
211
212 val = from << 8 | to;
213
214 if(ioctl(fd, SOUND_MIXER_PRIVATE2, &val)) {
215 perror("AD1848 mixer reroute");
216 return 1;
217 }
218 }
219
220 return 0;
221}
222