TVout reverse engineering GF4 etc.

[Dirk Thierbach <dthierbach-Mmb7MZpHnFY@public.gmane.org>]

Hi,

I read on http://nouveau.freedesktop.org/wiki/TestersWanted that
you're looking for information for the integrated tvout
functionality. I'm the author of nvtv, and I know some bits and pieces
about that subject, so maybe we can pool efforts.

The TV encoder used in the NVidia GPUs may be a Zoran CVE IP core,

http://www.zoran.com/products/literature/index.html

For the GF4 MX, it's possibly a CVE2, and for the newer cards, it may be
one of the later versions. The Matrix G400 Maven TV encoder also seems to 
be a CVE2, but extended with extra registers.

There's no register information on the CVE cores, but the Matrox people
have figured out some of them, and I've guesses about some of the
others.

I've seen from the code at sourceforge that you've already found the
index and data register for this core. The other registers in the 0x00d000
area look like they are MUX control for the DACs, control for a scaler
before the image is sent to the encoder (overscan, centering, flicker
filter coefficients and vertical interpolation coefficients).

All this is of course just guesswork, and some or all of it may be wrong.

I'd appreciate it if one of you could point me to some place to
document and exchange that information. If possible, I'd also like to have
a look at any register dumps you have, especially for newer cards; maybe
I am able to spot something.

Finally, if any of you has such a card and access to a scope (unfortunately,
I don't), it should be easy to verify the meaning of some of the encoder
registers (and maybe to guess some more).

- Dirk