
Here are a few hints if you have trouble to make bttv & xawtv work:


general
=======

* Check the PROBLEMS file in Ralph's bttv Documentation

* There are a few known incompatibilities, see below.

* The insmod options for the modules are documented in the
  MODULES file.  Use the "verbose=" and "debug=" args to make
  the modules more verbose.

* Just in case you don't know: With the "dmesg" command you can
  display the (last 4k of) kernel/module messages.

* Try a newer version of the X-Server (if available).

* If you upgrade xawtv and something does'nt work any more, please
  check the Changes file before sending bug reports...

* There are some X-Servers with a buggy XF86VidMode extention around.
  xawtv has a "-x" switch do disable the usage of the XFree extentions,
  this should fix the hangs on startup.


video
=====

* Make sure capture is turned on (xtvscreen starts up with capture
  off)

* Black screen, no picture at all:  Bad, probably the video frame buffer
  address is wrong.
  The bttv module has a vidmem=0x??? argument, so you can pass the
  correct one.  xawtv should print it (if the X-Server supports DGA),
  you can check the X-Server startup messages and /proc/pci too.
  Note: The vidmem= arg will be shiftet by 20 bits, you need the first
  three (hex-)digits of the frame buffer address only!!!

* Black screen after some time of normal operation: try to reload the
  bttv module.

* Blue Screen:  That's what you get if there is no input signal
  (Composite1 and no input source connected, sometimes happens with
  the wrong tuner type too).  The Blue Screen already comes from
  the Grabber card, so the interaction between Grabber and Graphics
  board already works fine.

* noisy, sort-of-white screen:  There is no TV Station tuned in.
  Possible reasons:
   - There is really no station present on that channel...
   - tuner module not loaded
   - Wrong tuner type. You can set the tuner type with the "type="
     insmod argument of the tuner module, see the MODULES file for
     details.
   - Wrong channel map (the channel-to-freqency mapping is
     different in different countries)
   - some trouble with the i2c bus, see below

* Trouble with TrueColor mode:  It's impossible to find what color depth
  the X-Server uses internally, you might have to use the -b switch to
  tell if it runs 24 or 32 bpp.  Both xawtv and v4l-conf have this switch.


sound
=====

* it might be nessesary to initialize the sound card with a
  "insmod sound" to get sound at all.

* With stereo cards you need the msp3400 module.

  There is some trouble with the MIRO cards:  They can do both
  mono (without msp3400 chip) & stereo (using msp3400), but nobody
  knows how to kick them into stereo mode.
  Result: it works even without msp3400, but loading the msp3400
  does'nt give stereo sound...

* For radio support (WinTV/Radio) you have to do "insmod radio=1"


if it still does'nt work...  --  hardware problems/conflicts
============================================================

* As far I know, the bttv driver can't do IRQ sharing, make sure it
  has its own interrupt.

* There are reports that the tuner works only if the *graphic board*
  has its own IRQ.  Don't ask me why...

* Sometimes there are memory conflicts beetween bttv and some other
  card.  With the remap insmod option of the bttv module you can move
  the memory of the bt848 chip to some other place.

* If you have to boot Win95 first to make the grabber board work, you
  might want to save /proc/pci before and after running Win95 and look
  for changes to track the problem down.

* /proc/pci, /proc/interrupts and /proc/ioports are your friends...


Known problems / incompatibilities
==================================

o	There are some problems with the i2c bus sometimes (you'll get
        i2c i/o error messages in the syslog).  I got all sorts of
	strange reports about this problem.  Seems at least some boards
	(my one is fine) don't work reliably if they get hot or something
	like that...

	One (but maybe not the only) reason for these i2c bus problems
	are memory conflicts.  Playing around with the remap insmod
	option might help.


[Alan on linux-kernel]

o       Some SiS boards it doesnt work on. I don't know if it works on
        the new SiS socket 7 stuff (5598 etc) but I'd like to know

o       S3 video cards it flickers when windows are scrolling etc. Windows
        & Linux. You cant DMA video to an S3 while it is using the onboard
        accelerator

o       Lot of noise with 3c59x ethernet. Caused by the latency for the
        3c59x having to be really high to avoid a silicon bug.

[Ralph, see also his PROBLEMS file]

o	Some S3 cards (mostly Trio 64) don't work with XFree (but with
	AccelX).



More hints/suggestions/corrections/updates are welcome,

  Gerd


--
Gerd Knorr <kraxel@cs.tu-berlin.de>

