int detect_trace=0; /* * Detect Trace will trace the audio device detection and operation. However * this feature should only be enabled when requested by the technical support * personnell. */ int max_intrate=100; /* * Max intrate sets up the maximum number of interrupts/second. This * in turn sets up the minimum buffer fragment size. The default value is 100 * It equals to about 50 fps frame rate which should be good for most * applications (including games). However some special applications * may require lower latencies. In such cases a higher value such as 500 or 1000 * may be needed. The minimum latency will be roughly 2/max_intrate * seconds. However the exactl latency depends on what the application has * requested using ioctl(SNDCTL_DSP_SETFRAGMENT). A value of zero means * OSS doesn't try to limit interrupt rate. * * Lower latencies require higher interrupt rates which in turn causes higher * system overhead. In addition using max_intrate values higher than system's * internal clock rate (HZ) may not make any actual improvement. * * Some devices use fixed fragment size and this parameter will not have any * effect with them. For example the Digi32 and Digi96 devices work in this way. */ int src_quality=3; /* * The src_quality setting defines the precision of the software based sample * rate conversion algorithm used by OSS. This setting doesn't affect possible * hardware level conversions done by the devices themselves. Using higher * quality setting gives better quality while lower settings consume less * CPU time. * * Possible values are: * 0 - D lowest quality (normally equals to 1=low quality) * 1 - L low quality (spline interpolation) * 2 - M medium quality (lagrange interpolation) * 3 - H high quality (DEFAULT) * 4 - HX high quality (high quality with extra precision) * 5 - P production quality * 6 - PX production quality (prod quality with extra precision) */ int ac97_amplifier=-1; /* * When set to 1 this option enables the speaker power amplifier feature of * AC97 codec (if available). Some boards have this inverted, so if necessary * 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. */ int ac97_recselect=0; /* * When set to 1 this option enables independent recording source * selection for the left and the right channel on AC97 devices. In this way * it's 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 it's only possible to * select the recording source by using a fully OSS 4.0 compatible mixer * program such as ossxmix. */ int cooked_enable=1; /* * 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 don't 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. This option should not be changed * without wery strong reason. */ int dma_buffsize=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. This option must not be * changed unless it's absolutely necessary. */ int flat_device_model=0; /* * OSS version 4.0 and later use two level device model where multiple audio * engines supported by the device (hardware mixing or vmix) are hidden behind * the same device file. When this device file is opened OSS will connect the * application to the first available subdevice. In this way multiple * applications can use the same device file at the same time. * * If this option is set to 0 OSS will use the earlier (OSS 3.x) device scheme * where all devices are directly visible to the applications. This may be * necessary with some custom applications that depend on the old * behaviour. */ int vmix_disabled=0; /* * The virtual mixer subsystem can be disabled by setting this configuration * option to 1. By default the value is 0 which enables virtual mixer. */ int vmix_loopdevs=0; /* * 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. This setting should be left to 0 unless * there are specific reasons to enable the loopback devices. */ int vmix_no_autoattach=0; /* * 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 * the device(s). */ int excl_policy=0; /* * By default the O_EXCL open() flag can be used 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. */ int mixer_muted=0; /* * By default mixer volume controls will be set to audible levels * when OSS drivers are loaded. However in some systems it may * be necessary to default to lower levels to avoid feedback or * noise. Set mixer_muted to 1 to use low default levels and to * 0 to select audible levels. * * Note that just few OSS drivers support this option. */