According to the docs VBLANK should be set to 22/34 in autoconfig, but
according to the register definitions, it defaults to 20. If disable
setting the register, it does in fact get set to 20 rather than 22. I
think if this value was manually set to ~24 the vbi data at the top
would no longer be visible and the picture would line up with what I
normally see on my tv. I also noticed that VACTIVE was set to 580 and
when I let this autoconfig, it sets it to 487 (I'm not sure if that
adversely affects anything).

Actually, everything in the vbi_reg_setup (0x474-0x477) probably
doesn't belong there and could be setup through autoconfig.

On 5/26/05, Bryan Mayland <[EMAIL PROTECTED]> wrote:
> The datasheet also says:
> "In autoconfiguration mode, the default value for the vertical blanking
> delay, VBLANK
> (0x474 an 0x475) is set to 22 and 34, respectively, for each video
> standard."
> 
> So maybe we should just let it autoconfigure.
> 
> Also, I've never noticed this before, but why does vbi_reg_setup write
> to 0x474 and 0x475?  These are only VBLANK and VACTIVE, so those should
> be set up when setting the standard, right?  Granted, VBLANK controls
> the size of the VBI region, but I don't think this is the place to set
> it, especially considering it doesn't currently take video standard into
> account.
> 
> Ben Lancki wrote:
> 
> >This was one of the last visual things bugging me with the driver. The
> >screen always appeared vertically offset by 10-15 pixels from the
> >broadcast video. According to the cx25840 documentation, VBLANK should
> >be 22 for NTSC and 34 for PAL/SECAM. This patch sets it to 22 or 34
> >depending on the card region (although I can only test NTSC). It was
> >originally set to 36 so probably NTSC people will be the only ones to
> >notice any big difference.
> >
> >
> 
> 
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