Audio driver for CM8338/CM8738 chips by Chen-Li Tien


HARDWARE SUPPORTED
================================================================================
C-Media CMI8738


DRIVER PARAMETER
================================================================================

  Some functions for the cm8738 can be configured in Kernel Configuration
  or modules parameters. Set these parameters to 1 to enable.

  mpuio:	I/O ports base for MPU-401, set to 0 if you don't need it.
  fmio:		I/O ports base for OPL-3, set to 0 if you don't need it.
  joystick:	Enable joystick. You will need to install Linux joystick
		driver (gameport.o).
  spdif_inverse:Inverse the S/PDIF-in signal, this depends on your
		CD-ROM or DVD-ROM.
  spdif_loop:   Enable S/PDIF loop, this route S/PDIF-in to S/PDIF-out
                directly, some CD-ROM support digital audio so you
		can use this option to play music on an amplifier.
  spdif_out:	Set to 1 to enable PCM data output through S/PDIF-out
		so you can use an external amplifier.
  use_line_as_rear:Set to 1 if you want to use line-in jack as
                rear-out(surround-out).
  use_line_as_bass:Set to 1 if you want to use line-in jack as
                Center/Bass output.
  use_mic_as_bass:Set to 1 if you want to use mic-in jack as center/bass
		output.
  mic_boost:	Set to 1 to enable mic boost.
  hw_copy:	Set to 1 to copy PCM and analog of front speakers to
		surround speakers.

Q & A
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Q: How to use AC3 audio for DVD player?
A: This is enabled by default.
   For MPlayer, use -ac hwac3 to play through S/PDIF-out.
   For Xine player, edit your xine config file to contains
   "audio.a52_pass_through:1", or change it in its GUI interface.

Q: How to use multi-channel for DVD player?
A: This is supported by default.
   For MPlayer, use -channels 6 to enable 5.1 channels support.
   For Xine player, edit your xine config file so it contails
   "audio.five_lfe_channel:1" to use it, or change it in its GUI interface.

Q: Why audio cannot be heard from surround speakers?
A: You need to set the hw_copy parameter as 1, please not the Center/Bass
   speakers will be still silent for general audio, this mode will be disabled
   if AC3 or multl-channel PCM playback (ie. DVD).

Q: My sound card (or on-board audio) has only 3 jacks, how to play multi-channel
   audio?
A: You can use use_line_as_rear and use_mic_as_bass to turn line-in jack as
   rear-out, and mic-in jack to center/bass output.

Q: How to play PCM through S/PDIF-out?
A: You need the spdif_out option to output general (mono or stereo) PCM streams
   from S/PDIF-out, however, this is limited to 44.1k/48k 16-bit stereo PCM.
   Note: In this mode, PCM volume will not function for streams play thru
   S/PDIF-out.

Q: How to disable legacy devices support without recompile?
A: Set mpuio as 0 to disable MPU401. The mpu401 module will still be loaded.
   Set fmio to 0 to disable FM. The opl3 module will still be loaded.
   Set joystick as 0 to disable gameport support. The gameport module will
   still be loaded.