[13:29][jcp@phoenix]
[~] > dmesg | grep bttv
bttv: driver version 0.9.12 loaded
bttv: using 8 buffers with 2080k (520 pages) each for capture
bttv: Bt8xx card found (0).
bttv0: Bt878 (rev 17) at 0000:00:08.0, irq: 10, latency: 64, mmio: 0xdfdfe000
bttv0: detected: Leadtek WinFast TV 2000 [card=34], PCI subsystem ID is 107d:6606
bttv0: using: Leadtek WinFast 2000/ WinFast 2000 XP [card=34,autodetected]
bttv0: gpio: en=00000000, out=00000000 in=00bff119 [init]
bttv0: using tuner=3
bttv0: i2c: checking for MSP34xx @ 0x80... not found
bttv0: i2c: checking for TDA9875 @ 0xb0... not found
bttv0: i2c: checking for TDA7432 @ 0x8a... not found
bttv0: registered device video0
bttv0: registered device vbi0
bttv0: registered device radio0
bttv0: PLL: 28636363 => 35468950 .. ok
bttv0: add subdevice "remote0"

bt878 9008 0
tuner 16908 0
bttv 142252 1 bt878
video_buf 16708 1 bttv
v4l2_common 4928 1 bttv
btcx_risc 3848 1 bttv
videodev 7424 1 bttv
snd_bt87x 11140 1

/* Audio Routing for "WinFast 2000 XP" (no tv stereo !)
gpio23 -- hef4052:nEnable (0x800000)
gpio12 -- hef4052:A1
gpio13 -- hef4052:A0
0x0000: external audio
0x1000: FM
0x2000: TV
0x3000: n.c.
Note: There exists another variant "Winfast 2000" with tv stereo !?
Note: eeprom only contains FF and pci subsystem id 107d:6606
*/

bash-2.05b# lspci | grep Multimedia
00:08.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)
00:08.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)
00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233/A/8235 AC97 Audio Controller (rev 40)

cx8800 release notes
====================
 
This is a v4l2 device driver for the cx2388x chip.
 
 
current status
==============
 
video
 Basically works.  Some minor quality glitches.  For now
 only capture, overlay support isn't completed yet.
 
audio
 Doesn't work.  Also the chip specs for the on-chip TV sound
 decoder are next to useless :-/
 Most tuner chips do provide mono sound, which may or may not
 be useable depending on the board design.  With the Hauppauge
 cards it works, so there is at least mono sound.  Not nice,
 but better than nothing.
 
vbi
 not implemented yet (but I don't expect problems here, just
 found no time for that yet).
 
 
how to add support for new cards
================================
 
The driver needs some config info for the TV cards.  This stuff is in
cx88-cards.c.  If the driver doesn't work well you likely need a new
entry for your card in that file.  Check the kernel log (using dmesg)
to see whenever the driver knows your card or not.  There is a line
like this one:
 
 cx8800[0]: subsystem: 0070:3400, board: Hauppauge WinTV \
  34xxx models [card=1,autodetected]
 
If your card is listed as "board: UNKNOWN/GENERIC" it is unknown to
the driver.
 
You can try to create a new entry yourself, or you can mail me the
config information.  I need at least the following informations to
add the card:
 
 * the PCI Subsystem ID ("0070:3400" from the line above, "lspci -v"
   output is fine too).
 * the tuner type used by the card.  You can try to find one by
   trial-and-error using the tuner=<n> insmod option.  If you
   know which one the card has you can also have a look at the
   list in CARDLIST.tuner
 
Have fun,
 
  Gerd
 
--  
Gerd Knorr <kraxel@bytesex.org> [SuSE Labs]

/* Audio Routing for "WinFast 2000 XP" (no tv stereo !)
                gpio23 -- hef4052:nEnable (0x800000)
                gpio12 -- hef4052:A1
                gpio13 -- hef4052:A0
            0x0000: external audio
            0x1000: FM
            0x2000: TV
            0x3000: n.c.
          Note: There exists another variant "Winfast 2000" with tv stereo !?
          Note: eeprom only contains FF and pci subsystem id 107d:6606
         */

bttv0: gpio: en=00000000, out=00000000 in=00bff161 [init]
bttv0: using tuner=3
bttv0: i2c: checking for MSP34xx @ 0x80... not found
bttv0: i2c: checking for TDA9875 @ 0xb0... not found
bttv0: i2c: checking for TDA7432 @ 0x8a... not found
tuner: chip found @ 0xc2
tuner: type set to 3 (Philips (SECAM+PAL_BG) (FI1216MF, FM1216MF, FR1216MF))
bttv0: registered device video0
bttv0: registered device vbi0
bttv0: registered device radio0
bttv0: PLL: 28636363 => 35468950 .. ok
bttv0: add subdevice "remote0"
bt878: AUDIO driver version 0.0.0 loaded

Starting with release 0.7.41 bttv has a number of insmod options to
make the gpio debugging easier:
 
bttv_gpio=0/1  enable/disable gpio debug messages
gpiomask=n  set the gpiomask value
audiomux=i,j,... set the values of the audiomux array
audioall=a  set the values of the audiomux array (one
   value for all array elements, useful to check
   out which effect the particular value has).
 
The messages printed with bttv_gpio=1 look like this:
 
 bttv0: gpio: en=00000027, out=00000024 in=00ffffd8 [audio: off]
 
en  = output _en_able register (BT848_GPIO_OUT_EN)
out = _out_put bits of the data register (BT848_GPIO_DATA),
 i.e. BT848_GPIO_DATA & BT848_GPIO_OUT_EN
in  =  _in_put bits of the data register,
 i.e. BT848_GPIO_DATA & ~BT848_GPIO_OUT_EN

Module snd-bt87x
  ----------------
 
    Module for video cards based on Bt87x chips.
 
    digital_rate - Override the default digital rate (Hz)
 
    Module supports up to 8 cards.

Module snd-via82xx
  ------------------
 
    Module for AC'97 motherboards based on VIA 82C686A/686B, 8233,
    8233A, 8233C, 8235 (south) bridge.
 
    mpu_port - 0x300,0x310,0x320,0x330, otherwise obtain BIOS setup
    [VIA686A/686B only]
    joystick - Enable joystick (default off) [VIA686A/686B only]
    ac97_clock - AC'97 codec clock base (default 48000Hz)
    dxs_support - support DXS channels,
    0 = auto (defalut), 1 = enable, 2 = disable,
    3 = 48k only, 4 = no VRA
    [VIA8233/C,8235 only]
    ac97_quirk  - AC'97 workaround for strange hardware
                  See the description of intel8x0 module for details.

Note: for the MPU401 on VIA823x, use snd-mpu401 driver
   additonally.  The mpu_port option is for VIA686 chips only.

config SND_BT87X
        tristate "Bt87x Audio Capture"
        depends on SND
        help
          Say 'Y' or 'M' to include support for recording audio from TV cards
          based on Brooktree Bt878/Bt879 chips.

tvtime-command SCREENSHOT "current.png"

11. How can I map audio to my digital output?
 
Many bt878-based cards also support digital capture of the audio. This can be accessed using the btaudio kernel module, which registers an OSS sound device that supports 32 KHz audio capture. On a capable card, loading the module gives something like this in your system logs:
 
    btaudio: driver version 0.7 loaded [digital+analog]
    btaudio: Bt878 (rev 2) at 01:0b.1, irq: 6,
             latency: 64, mmio: 0xf16ff000
    btaudio: using card config "default"
    btaudio: registered device dsp2 [digital]
    btaudio: registered device dsp3 [analog]
    btaudio: registered device mixer1
 
On my system /dev/dsp2 can now be used to read digital audio from the card at 32 KHz. This can be then sent out to an arbitrary soundcard using a program such as sox.
 
    sox -r 32000 -w -t ossdsp /dev/dsp2 -t ossdsp /dev/dsp
 
This command reads the input at 32 KHz from /dev/dsp2 and writes it out to my soundcard at /dev/dsp. Having this run while using tvtime will enable you to perform arbitrary maps of the audio, such as playing it out the digital output of your soundcard.

bt878                   9008  0
tuner                  16908  0
bttv                  142252  2 bt878
video_buf              16708  1 bttv
v4l2_common             4928  1 bttv
btcx_risc               3848  1 bttv
videodev                7424  2 bttv