When set to 1 this option enables independent
recording source selection for the left and the right channel
on AC97 devices. In this way its possible to record audio
streams so that (for example) the left channel signal comes
from the microphone and
the right channel signal from line-in. However when this
option is enabled its only possible to select the recording
source by using a fully OSS 4.0 compatible mixer program such
Default: 0 - recording source is common to both channels.
When set to 1 this option enables the speaker power
amplifier feature of AC97 codec (if available).
Some boards have this inverted, so this feature can be
disabled by setting this option to 0.
Affects all AC97 based audio devices in the system.
Default: -1=autodetect correct setting.
By default OSS will let applications to use sampling
rates and formats that are not supported by the hardware.
Instead OSS performs the necessary format conversions in
software. Applications that dont tolerate this kind of
conversions usually disable them by using features of the OSS
API (SNDCTL_DSP_COOKEDMODE). If this option is set to 0 then
the format conversions will be disabled for all applications
and devices unless the application explicitly enables them.
Default: 1 - conversions are enabled.
This option should not be changed without very strong reasons.
Internal debugging (do not change). Default: 0
By default OSS will allocate audio DMA buffers with some
system dependent default size (usually 64k but sometimes
smaller). It is possible to change this default allocation by
setting this option. Value of 0 means that the default size
will be used. Value between 16 and 128 (kilobytes) can be used
if the default size is not suitable for some reason.
Default: 0 - system dependent buffsize.
This option mustnt be changed unless its absolutely necessary.
Set the maximum number of interrupts per second.
A value of 0 means the number is unlimited.
Default: 100 interrupts per second which equals to about
10 msec minimum latencies.
The virtual mixer subsystem can be disabled by setting
this configuration option to 1.
Default: 0 - virtual mixer is enabled.
Optionally the virtual mixer subsystem can create
special loopback audio devices that can be used to record the
output mix sent to the device. This option tells how many
loopback devices will be created (0, 1 or 2). If there are
multiple audio devices in the system the all of them will have
the same number of loopback devices.
Default: 0 - no loopback devices are created.
This setting should be left to 0 unless there are specific
reasons to enable the loopback devices.
By default (0) the low level
drivers for most sound cards will automatically
attach virtual mixer (vmix) to the primary audio devices of the cards.
In some situations it may be necessary to attach virtual mixer using
nonstandard parameters. If vmix_no_autoattach is set to 1 then user
can use vmixctl attach command to attach virtual mixer manually to
Default: 0 - Automatically attach virtual mixer.
The O_EXCL open() flag can be used by programs to bypass the
virtual mixer. Setting excl_policy to 1 or 2 makes OSS ignore O_EXCL.
A setting of 1 ignores O_EXCL from all but root processes,
while a setting of 2 always ignores O_EXCL.
Default: 0 - Do not ignore O_EXCL.
By default OSS will set most volume controls to audible level.
If this causes problems then its possible to ask OSS to set
the levels to zero when the drivers are loaded. However the
levels saved with the savemixer utility will get loaded few
moments later when all OSS drivers have been started. Note that
just some of the OSS drivers honor this setting.
Values: 0 (default) - Use audible volumes, 1 - Set volumes to low.