Driver Configuration

Configuration Overview

bt848x driver consults driver configuration file for its behavior decision. driver.conf(4) manual page describes detailed notation and concept.

bt848x driver configuration file is located at /platform/`uname -m`/kernel/drv/bt848x.conf. It is read when driver is loaded. Driver will ignore change of configuration file while it is loaded in kernel space.

Configuration strategy

bt848x configures its behavior in following order:
  1. First, consult predefined parameter set from PCI subsystem ID and PCI subsystem vendor ID. We call this auto-identification in this document. Generally, auto-identifiable cards needs not further configuration. Not all cards have these IDs, so driver cannot always figure out card identification.
  2. Next, if 'card-type' is specified in configuration file, consult predefined parameter set according to 'card-type'. Not all cards has 'card-type' number.
  3. And last, other parameters is taken from configuration file. Even if a card is auto-identifiable or has 'card-type' number, you can overwrite parameters in this stage. If a card is not auto-identifiable and has not 'card-type' number, you must supply many parameters in this stage.

Special notation for multiple card instances

If you have more than 1 card in a machine, you should specify parameters with comma-separated, except 'video-mux' and 'audio-mux' (parameter detail is described later). For example:
card-type=11,13;	# type of card #1 is 11, and #2 is 13
video-inputs=3,4;	# number of inputs equipted card #1 is 3, #2 is 4
video-mux0=1,2,3;	# card #1 video multiplexer config
video-mux1=2,0,1,3;	# card #2 video multiplexer config

Parameters in configuration file

Type of card. See Supported / Unsupported Capture Card or /opt/KSWbt8x8/doc/carddef.doc. By default, 0 (unknown or generic card) is assumed.

This parameter affects all other parameters. But, this parameter is evaluated ahead of them, so you can overwrite other parameters.

Number of audio multiplexer input. Normally '1' and it is default. Note: All sound-related ioctls would fail if '0' is specified. So, '1' is adequate value even if card does not have any audio input.
Video channel of tuner input (normally '0'). If card does not have tuner, specify '-1'. By default, '-1' is assumed.
Video channel of S Video (separated video) input. If card does not have S Video input, specify '-1'. This is normally '2', but '-1' is assumed by default.
Mask of GPIO(Bt8x8's general purpose input/output pins) output. This value is used as output enable bit. If you don't understand what this parameter is, specify '0' and it is default. Specifying other than '0' is possible to harm hardware, so please be prudence in trying new value.
Set of video signal multiplexer (up to 16) values in following format:
video-muxN = muxval_of_1ch, muxval_of_2ch, muxval_of_3ch, ...;
where N is instance number of the card.
Set of audio signal mutiplexer values in following format:
audio-muxN = muxval_of_tuner, muxval_of_radio,
             muxval_of_internal, muxval_of_external, muxval_of_mute;
where N is instance number of the card.
PLL reference clock frequency. Specify '0' for card without PLL, '28' for 28MHz clock, '35' for 35MHz clock. You may need this if picture is monochrome.
Type of tuner. See Supported / Unsupported Capture Card. If card doesn't have tuner, specify '4' and it is default. Please do not ask me why '4' is used.
Type of norm standard variant. This parameter is valid only if 'tuner-type' paramter is 22 (TEMIC 4046FM5) or 24 (Philips FQ1216ME).

tuner-type=22 tuner-type=24
tuner-norm-variant 0x69 0x64 0x6c others 0x69 0x6c others
If tuner has ability to tune radio, specify '1'.
Specify AFC (automatic frequency control) mode of TV tuner.
0no feedback mode. (default)
1no feedback mode, but returns error when tuner cannot detect carrier.
2carrier detection mode.
3signal intensity feedback mode.
More precise tuning is performed in this order, but more response time is needed. '0' is sufficient for almost case.

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