
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* Try a newer version of the X-Server (if available).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, i/o error messages in the syslog.
     If this is a Hauppauge board, try to enable the msp3400 reset
     code in the bttv driver (see bttv/driver/Makefile).

* Trouble with TrueColor mode (image spread across the screen): 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.

* Picture is fine, but it is 256 pixels off the window (Millennium I
  eh?).  The framebuffer address is wrong (off by 1024 == 0x400 byte),
  you can correct this with the vidmem insmod option.  Newer bttv
  version take both the old 3-digit and full 8-digit addresses :-)
  xawtv works only with the '-x' option, becauce DGA reports the wrong
  address for the framebuffer.  Therefore the sanity check failes
  unless DGA is disabled...


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	i2c trouble on Hauppauge boards is solved (by resetting the
	msp3400 chip using it's reset line) -- check the driver
	Makefile, there you can enable this piece of code.

[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>

