[Savage40] Thinkpad T23 and external monitor 1680x1050

[Tim Roberts]

Gianluca Interlandi wrote:
> I have a Thinkpad T23 with S3 video card. I have bought a Philips 20inch 
> 1680x1050 widescreen monitor (200w6cb) which I attach to my laptop through 
> the VGA connector. I use the options "UseBios" "FALSE" and "CrtOnly" 
> "TRUE".
>
> It works fine at the full resolution of 1680x1050 and 32-bit color depth. 
> However, if I try to watch a DVD movie with mplayer or xine the image 
> starts flickering and there are strange horizontal lines. This does not 
> happen if I watch a mpeg file containing a movie at low resolution. If I 
> turn down the color depth to 16-bit everything is fine and I'm able to 
> watch DVDs. What could the reason be?

My first guess would be a memory bandwidth issue.  1680x1050x4 at 70Hz
is 500MB/s just for refresh, and since this is a UMA device, the chip is
competing for main memory with the other chip users.  It may be that
there isn't enough bandwidth for it to pull fullscreen video from an
overlay surface at the same time.

There are a large number of memory tuning parameters in the Savage
streams engine for deciding when it has to switch to the overlay
surface, and how much extra time to allow to switch back.  I'm not sure
we tuned those for a 1680x1050 resolution.

-- 
Tim Roberts, timr at probo.com
Providenza & Boekelheide, Inc.