deva-ctrl-usb.so

Sound driver for USB audio devices

---

You must be root to start this driver.

---

Syntax:

Direct invocation (also causes a new io-audio process to start):

io-audio -d usb [opt[,opt...]] &

Mounting (requires that io-audio already be running):

mount -Tio-audio [-oopt[,opt...]] /lib/dll/deva-ctrl-usb.so &

Runs on:

Neutrino

Targets:

x86

Options:

busno=bus

The bus number of the USB controller.

devno=dev

The USB address of the device.

did=did

The device ID of the device.

iface=iface

The audio control interface number.

max_fragsize=num

Maximum fragsize (the default is 8 KB).

rx_voices=num

The number of RX voices.

tx_voices=num

The number of TX voices.

vid=vid

The vendor ID of the device.

For card options that apply to all sound drivers, see the entry for io-audio.

Description:

The deva-ctrl-usb.so shared object is a device driver DLL used by the io-audio manager. It uses the API described in the Audio Developer's Guide.

While deva-ctrl-usb.so is running, you can use applications with sound, and those that control the sound-system (e.g. mixer).

If you're starting the driver to target a particular audio function, you must provide the vid, did, busno, devno, and iface options. The USB device must be inserted before you start or mount the driver.

When the device is removed, the audio DLL is unmounted from io-audio, but the io-audio manager itself continues to run (after you re-insert the device, you can run mount -Tio-audio deva-ctrl-usb.so). You have to slay io-audio if you want it to be terminated.

---

Some USB Host controllers are restricted in the number of transfer descriptors available, so adjustments to either the audio driver's max_fragsize or the USB Host controller driver's TD pools (num_td=xx) may be required for successful isoch transfers. Graphics drivers run at a higher priority than applications, but they shouldn't run at a higher priority than the audio, or else breaks in the audio occur. You can use the on command to adjust the priorities of the audio and graphics drivers.

---

Examples:

Invoke deva-ctrl-usb.so directly from io-audio:

io-audio -d usb &

Mount deva-ctrl-usb.so (io-audio must be running):

mount -Tio-audio /lib/dll/deva-ctrl-usb.so &

Errors:

When an error occurs, deva-ctrl-usb.so sends a description of the error to the system logger (see slogger).

See also:

io-audio, mixer

Audio Developer's Guide