sound/designs/oss-emulation.rst

2 Notes on Kernel OSS-Emulation
13 as add-on kernel modules, snd-pcm-oss, snd-mixer-oss and snd-seq-oss.
18 is called.  The alias is defined ``sound-service-x-y``, where x and y are
22 Only necessary step for auto-loading of OSS modules is to define the
25 	alias sound-slot-0 snd-emu10k1
27 As the second card, define ``sound-slot-1`` as well.
29 ``alias sound-slot-0 snd-card-0`` doesn't work any more like the old
38 after the corresponding OSS-emulation module is loaded.  Don't worry
79 snd-pcm-oss and snd-rawmidi.  In the case of PCM, the following
80 options are available for snd-pcm-oss:
93 	options snd-pcm-oss adsp_map=2
100 	options snd-pcm-oss adsp_map=0,2
103 available for snd-rawmidi:
116 	options snd-rawmidi midi_map=2
122 As default, ALSA emulates the OSS PCM with so-called plugin layer,
123 i.e. tries to convert the sample format, rate or channels
131 (zero-based), Y the PCM device number (zero-based), and ``p`` is for
132 playback and ``c`` for capture, respectively.  Note that this proc file
133 exists only after snd-pcm-oss module is loaded.
155 non-block
156 	force non-block open mode
157 partial-frag
158 	write also partial fragments (affects playback only)
159 no-silence
162 The ``disable`` option is useful when one stream direction (playback or
166 conversion and useful for MMAP-applications.
167 For example, to playback the first PCM device without plugins for
173 While quake wants only playback, you may append the second command
183 The block and non-block options are used to change the behavior of
187 the file when it's busy. The -EBUSY error is returned in this case.
190 module option of snd-pcm-oss.  For using the blocking mode as default
194 	options snd-pcm-oss nonblock_open=0
196 The ``partial-frag`` and ``no-silence`` commands have been added recently.
207 	% cat /proc/asound/card0/pcm0p/oss > /somewhere/oss-cfg
212 	% cat /somewhere/oss-cfg > /proc/asound/card0/pcm0p/oss
228 from "PCM Playback Volume" and "PCM Playback Switch" controls for the
229 playback direction and from "PCM Capture Volume" and "PCM Capture
240 SOUND_MIXER_BASS	Tone Control - Bass	0
241 SOUND_MIXER_TREBLE	Tone Control - Treble	0
252 SOUND_MIXER_OGAIN	Playback		0
266 The second column is the base-string of the corresponding ALSA
267 control.  In fact, the controls with ``XXX [Playback|Capture]
282 the base-string of the corresponding ALSA control, and the third the
287 proc file.  For example, to map "Wave Playback" to the PCM volume,
291 	% echo 'VOLUME "Wave Playback" 0' > /proc/asound/card0/oss_mixer
295 example, both "Wave Playback Volume" and "Wave Playback Switch" will
310 Note that when attempting to use a single device file for playback and
312 number of channels different in each direction.  Thus
332 ----------------------
334 10-channels 24bit (packed in 32bit) format.  Therefore you cannot mmap
335 the buffer as the conventional (mono or 2-channels, 8 or 16bit) format