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diff --git a/Documentation/sound/oss/Maestro3 b/Documentation/sound/oss/Maestro3 new file mode 100644 index 00000000000..a113718e803 --- /dev/null +++ b/Documentation/sound/oss/Maestro3 @@ -0,0 +1,92 @@ + An OSS/Lite Driver for the ESS Maestro3 family of sound chips + + Zach Brown, January 2001 + +Driver Status and Availability +------------------------------ + +The most recent version of this driver will hopefully always be available at + http://www.zabbo.net/maestro3/ + +I will try and maintain the most recent stable version of the driver +in both the stable and development kernel lines. + +Historically I've sucked pretty hard at actually doing that, however. + +ESS Maestro3 Chip Family +----------------------- + +The 'Maestro3' is much like the Maestro2 chip. The noted improvement +is the removal of the silicon in the '2' that did PCM mixing. All that +work is now done through a custom DSP called the ASSP, the Asynchronus +Specific Signal Processor. + +The 'Allegro' is a baby version of the Maestro3. I'm not entirely clear +on the extent of the differences, but the driver supports them both :) + +The 'Allegro' shows up as PCI ID 0x1988 and the Maestro3 as 0x1998, +both under ESS's vendor ID of 0x125D. The Maestro3 can also show up as +0x199a when hardware strapping is used. + +The chip can also act as a multi function device. The modem IDs follow +the audio multimedia device IDs. (so the modem part of an Allegro shows +up as 0x1989) + +Driver OSS Behavior +-------------------- + +This OSS driver exports /dev/mixer and /dev/dsp to applications, which +mostly adhere to the OSS spec. This driver doesn't register itself +with /dev/sndstat, so don't expect information to appear there. + +The /dev/dsp device exported behaves as expected. Playback is +supported in all the various lovely formats. 8/16bit stereo/mono from +8khz to 48khz, with both read()/write(), and mmap(). + +/dev/mixer is an interface to the AC'97 codec on the Maestro3. It is +worth noting that there are a variety of AC'97s that can be wired to +the Maestro3. Which is used is entirely up to the hardware implementor. +This should only be visible to the user by the presence, or lack, of +'Bass' and 'Treble' sliders in the mixer. Not all AC'97s have them. +The Allegro has an onchip AC'97. + +The driver doesn't support MIDI or FM playback at the moment. + +Compiling and Installing +------------------------ + +With the drivers inclusion into the kernel, compiling and installing +is the same as most OSS/Lite modular sound drivers. Compilation +of the driver is enabled through the CONFIG_SOUND_MAESTRO3 variable +in the config system. + +It may be modular or statically linked. If it is modular it should be +installed with the rest of the modules for the kernel on the system. +Typically this will be in /lib/modules/ somewhere. 'alias sound-slot-0 +maestro3' should also be added to your module configs (typically +/etc/modprobe.conf) if you're using modular OSS/Lite sound and want to +default to using a maestro3 chip. + +There are very few options to the driver. One is 'debug' which will +tell the driver to print minimal debugging information as it runs. This +can be collected with 'dmesg' or through the klogd daemon. + +One is 'external_amp', which tells the driver to attempt to enable +an external amplifier. This defaults to '1', you can tell the driver +not to bother enabling such an amplifier by setting it to '0'. + +And the last is 'gpio_pin', which tells the driver which GPIO pin number +the external amp uses (0-15), The Allegro uses 8 by default, all others 1. +If everything loads correctly and seems to be working but you get no sound, +try tweaking this value. + +Systems known to need a different value + Panasonic ToughBook CF-72: gpio_pin=13 + +Power Management +---------------- + +This driver has a minimal understanding of PCI Power Management. It will +try and power down the chip when the system is suspended, and power +it up with it is resumed. It will also try and power down the chip +when the machine is shut down. |