Mark Adams wrote:

> Some things that might help:
> 
> You'll need the TVon=1 option when you load the framebuffer module in
> order to enable the TV encoder.  You'll also need TVtype=1 (NTSC); the
> default is 2 (PAL).  With that done, the exact timings you put in the
> fb.modes files are fairly academic because the timing is then
> determined by what's needed for the TV encoder.  However, you do need
> a definition for the resolution that you're going to use (e.g.
> 720x480).

I have tried TV0n=1 and TVtype=1 and specifying mode=720x480.

> The actual timings can be found in the via_tv3.h or via_vt1622a.h
> files (depending on which TV encoder you have.  Do you know which it
> is?)

A close look at the motherboard shows a VT1622M, I'm running a VIA 
Epia-M10000 Nehemiah.

> Unfortunately, the data in those files is not in any way readable but
> there is a utility that can help you create the tables.  I'd need to
> look that out.  If it's licence is suitable I could pop it in with
> linux-viafb.

That could be handy, what's it called?

> I created an optimised 720x576 PAL mode for the VT1622A and Nicolas
> Huillard did the same for the VT1622.  Perhaps you'd like to make the
> NTSC versions?

I'm willing to give it a shot, but this will be my first foray into such 
stuff so it'll likely take a bit of time.  Could you explain how you 
went about it and what steps you took and I can start from there?

> There are, however, existing NTSC modes that should get you a picture.

As I said, I had it working with the via driver, but so far no joy here. 
  I really like the mpeg acceleration though so I want to make this work.

>> I've also tried with combinations of the bcast and laced options without
>> success.
> 
> Two different modes are supported for the resolutions supported by the
> TV encoder, one with overscan and one without.  You get the overscan
> version by putting 'bcast true' in your fb.modes file.
> 
> The laced option should not be used.  The interlace is created by the
> TV encoder and not by the graphics chip's CRTC (which should be
> generating a 720x480p60 picture).

Noted.  Thanks.

>> Ideally I'd like to see a configure option for default output (NTSC, PAL
>> or SECAM) at compile time but I have no idea what's involved with that.
> 
> The driver doesn't support SECAM.

That's ok, I meant to emphasize the idea of a compile time switch for 
default option, rather than support for SECAM

> The defaults are set by the 10 or so lines following the comment
> 'video mode' in via_fbobj.c.

I'll take a look at that and see what I can do.

Thanks for your help,

John

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