Re: C&T Chipset - help!

[Craig Oda <craig@example.com>]

On Tue, 30 Jan 1996 cybernet@example.com wrote:

> Can you give me an advise on X configuration with Chips and Technologies 
> CT65548 video chipset? I am trying to configure Sotec Pentium Notebook but 
> alas. A sort of running out of time now though..
> Yuri Anissimov, Cybernetech Corporation, (03) 3668-8089

The notebook homepage lists some dot clocks for CT65545:

In theory, the CT65545 is capable of a dot clock up to 65MHz, good enough to drive
1024x768x256 at a reasonable refresh rate. Unfortunately, XFree86 can't actually program
the dot clock to that rate: this appears to be a deficiency in the SVGA server. With the LCD
on, XFree86 sees only two dot clocks: 25.2 and 28.3. With the LCD off, XFree86 sees 25.2,
28.3, and 40.0.

Note that the commercial XInside server supports the CT65545 better: in particular, it can
program the dot clock up to the full 65MHz.

Using the LCD

If you just want to use the LCD, then it's fairly easy to configure XFree86. In particular, it
appears that all the sync pulses are just ignored. I've gotten by with this modeline (and
equivalents). 

Modeline "640x480" 28.3 640 640 640 640 480 480 480 480

If you prefer to do it right, this mode line seems to sync roughly correctly on a normal monitor
as well: 

Modeline "640x480"       28.3   640 664 760 800 480 491 493 525

Things get a bit more interesting if you try to use an LCD that's bigger than 640x480. On my
NEC Versa P, I found that I could go up to 704x600 with no trouble, and if I ran a server at
800x600 it also worked, but I had to turn the LCD off and on once after the server started
(via Fn-F3 or by closing the cover). Weird, but it works.


--------------------------------

I'm not sure how relevant the above information would be to the 
CT65548 chipset, but it might be something to start from.



----------------------
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