Date: Fri, 7 Nov 2003 17:18:31 -0500 From: Mathew Kanner <mat@cnd.mcgill.ca> To: freebsd-doc@freebsd.org Subject: suggested pcm replacement Message-ID: <20031107221831.GG94805@cnd.mcgill.ca>
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Hello All,
I'm not subscribed to the -doc list so please CC me. Anyway,
I've been pondering sound latetly and would like to see the man page
replaced with something like the attached.
Please note this is a first draft, I don't know how to write
man pages, a paragraph was ripped from the old manual, etc.
An emu10k1 manual should be simple in that the emu10k1 driver
supports the soundblaster 5.1, soundblaster live, dell EOM
soundblaster live. but NOT the audigy, audigy2, or extigy.
Cheers,
--Mat
--
It's impossible to awaken a man who is pretending to be
asleep.
- Navajo saying
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PCM -- FreeBSD PCM audio device infrastructure
PCM devices provide audio record and playback channels.
snd_driver_load="YES" in /boot/loader.conf, or
kldload snd_driver will load all available sound drivers.
snd_emu10k1_load="YES" in /boot/loader.conf, or
kldload snd_emu10k1 will load the EMU10K1 (SoundBlaster 5.1, etc) and all nessary components.
It is not recommened to include the sound modules in your kernel config.
SYSCTL
PCM sysctls are rooted in hw.snd
hw.snd.targetirqrate: Set the default block size such that
continous playback will achieve the IRQ rate. This can
overidden by applications.
hw.snd.report_soft_formats: Formats not supported by the device
are avaible to applications, uses internal format conversion.
hw.snd.verbose: Level of verbosity in /dev/sndstat output
hw.snd.unit: The default device for /dev/dsp
VCHANS
Each device can optionnaly supported more playback channels that
physical hardware provides. This feature can be set on a globally or
per device instance. VCHANs setting can only be manipulated while the
device is inactive.
Sysctls
hw.snd.maxautovchans: Global vchans settings, Setting 0 disables
VCHANs
hw.snd.pcm%d.vchans: current number of VCHANs for a device.
Setting the number of VCHANs to 0 disables this feature.
IOCTL
The driver supports most of the OSS ioctls(), and most applications
work unmodified (including popular mpeg players and linux binaries). A
few differences exist (the most important one is the ability to use mem-
ory-mapped access to the audio buffers). As a consequence, some applica-
tions may need to be recompiled with a slightly modified audio module.
See <sys/soundcard.h> for a complete list of the supported ioctls.
FILES
/dev/audio%d.%d Sparc-compatible audio device
/dev/dsp%d.%d Digitized voice device
/dev/dspW%d.%d Like /dev/dsp, but 16 bits per sample
/dev/dspr%d.%d Connected to a record codec
/dev/sndstat Current PCM status, including all channels and drivers.
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