[Openchrome-users] DVI-02 funkiness

[Luc Verhaegen]

On Fri, Apr 20, 2007 at 01:10:57PM +0200, Thomas Hellstr?m wrote:
> Philip Prindeville wrote:
> 
> Luc once moved VIA's GPIOI2C_ stuff over to the generic xf86i2c code.
> IIRC, While doing so, he altered some timings in order to make it work 
> with a chip he had on his mainboard. Those alterations made it fail 
> reading from the vt1623 device, it even got the device id wrong, so I 
> changed those timings back to something like what's in the VIA code to 
> make vt1623 working.
> 
> It's possible that the read timing needs more tweaking. Try to compare 
> the failing function with the corresponding one in the VIA code and see 
> if you can make it work
> 
> /Thomas

This development was done remotely. Over a 64kB line to Terry Lewis his 
Acer Aspire 135x. We both spent a long time on getting this done, as 
that sort of set-up is mostly about wasting time. VIA today still hasn't 
caught on.

The original code works np on hardware i support. The VT1623 TV encoder 
works perfectly on my K8M800 based laptop. The CH7019 on the aspire was 
working nicely too. So i guess that this timing issue is only present 
on certain northbridges.

Also, timing is as much an issue for the higher level code as the low 
level routines. I2C timing across the whole X hardware range should get 
very decent testing anyway.

Luc Verhaegen.
http://unichrome.sf.net/